Prenuptial Agreements in Michigan: 2026 Legal Requirements & Costs

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Michigan prenuptial agreements are legally enforceable contracts governed by MCL § 557.28 that require full financial disclosure from both parties, voluntary execution without duress, written form with notarization, and terms that are not unconscionable at the time of enforcement. The average attorney cost for drafting a Michigan prenup ranges from $750 to $2,400 as of March 2026, with hourly rates between $200 and $350 per hour. Michigan courts follow an equitable distribution system for divorce property division and retain the authority under MCL § 552.401 to review prenuptial agreements for fairness, even when validly executed, particularly if circumstances have substantially changed since signing.

Key Facts: Michigan Prenuptial Agreements

What Is a Prenuptial Agreement in Michigan

A prenuptial agreement in Michigan is a written contract between two people planning to marry that establishes how property, assets, debts, and spousal support will be handled during the marriage and in the event of divorce or death. Michigan formally refers to these agreements as antenuptial agreements under MCL § 557.28, which states that a contract relating to property made between persons in contemplation of marriage shall remain in full force after marriage takes place. The statute has been in effect since March 31, 1982, providing couples with the legal framework to define their financial rights and obligations before entering marriage.

Michigan operates under an equitable distribution system for divorce property division, meaning marital property is divided fairly but not necessarily equally. A prenuptial agreement allows couples to modify these default rules by specifying in advance how their property will be classified and divided. The agreement can protect separate property, clarify ownership of businesses or professional practices, limit or waive spousal support obligations, and establish procedures for dividing retirement accounts and other assets. Michigan courts generally uphold valid prenuptial agreements unless enforcement would be unconscionable or circumstances have changed substantially since the agreement was executed.

Under Michigan law, prenuptial agreements must meet specific requirements to be enforceable. The agreement must be in writing and signed by both parties before marriage. Both individuals must enter into the agreement voluntarily, without fraud, duress, or undue influence. Each party must provide full disclosure of their assets, debts, income sources, and financial circumstances. The terms must be fair and reasonable at the time of signing and not unconscionable. Additionally, both parties must have the mental capacity to understand the agreement and its implications. Michigan courts have consistently held that prenuptial agreements require a special duty of full disclosure that exceeds the standard due diligence requirements of ordinary contracts.

Michigan Prenuptial Agreement Laws and Recent Changes

Michigan prenuptial agreement law underwent significant judicial interpretation in recent years that affects how courts evaluate these contracts. While MCL § 557.28 remains the foundational statute, the Michigan Supreme Court has clarified that prenuptial agreements remain subject to the powers of courts to determine rights and asset distribution when a marriage dissolves. This means that two Michigan statutes, MCL § 552.23(1) and MCL § 552.401, give courts the authority to make decisions about property allocation and spousal support that a prenuptial agreement cannot completely override, allowing courts to award assets to a party who would otherwise receive insufficient support and maintenance.

The Michigan Legislature introduced Senate Bill No. 160 in the 2025-2026 session to enact the Uniform Premarital and Marital Agreements Act (UPMAA), which has been adopted by 29 states since its creation by the Uniform Law Commission in 1983 and update in 2012. If enacted, this legislation would modernize Michigan's prenuptial agreement framework by requiring agreements to be in a record and signed by both parties, making them enforceable without consideration, and defining duress as an incident involving a threat of illegal, humiliating, or unreasonable physical, financial, emotional, or social damage. The bill would apply only to agreements signed on or after its effective date and would not affect existing prenuptial agreements executed under current law. As of March 2026, this legislation remains under consideration and has not been enacted.

Michigan courts now exercise greater discretion to review prenuptial agreements for equitable enforcement compared to previous decades. A properly drafted prenuptial agreement will still be enforced, but courts overseeing divorce proceedings will review the agreement to determine whether enforcement is equitable based on circumstances at the time of divorce. This represents a shift toward protecting parties from agreements that may have been fair when signed but became unconscionable due to changes in health, employment, childcare responsibilities, or financial circumstances during the marriage. Courts are particularly likely to modify or decline to enforce prenuptial agreements in long-term marriages where one spouse sacrificed career opportunities to care for children or support the other spouse's professional advancement.

What Can Be Included in a Michigan Prenup

Michigan prenuptial agreements can address property division by specifying which assets will be classified as separate property versus marital property in the event of divorce. Under Michigan's equitable distribution system, only marital property is subject to division, defined as assets acquired during the marriage regardless of whose name appears on the title. A prenup can designate certain property as separate, such as real estate owned before marriage, business interests, investment accounts, inheritance rights, and personal property. The agreement can establish formulas for dividing appreciation in separate property, determine ownership percentages of jointly purchased assets, and protect assets from creditors of the other spouse. Michigan courts generally enforce these provisions when both parties made full disclosure of their assets and the terms were reasonable when executed.

Spousal support provisions in Michigan prenuptial agreements can limit, modify, or completely waive either party's right to receive alimony in the event of divorce. MCL § 552.23 establishes 14 factors courts consider when determining spousal support, including the length of marriage, ability of parties to work, source of income, needs and health of parties, prior standard of living, and contributions to the joint estate. A prenuptial agreement can override these factors by specifying that no spousal support will be paid or by establishing a fixed amount or formula based on the length of marriage. However, Michigan courts retain authority under MCL § 552.401 to review spousal support waivers for unconscionability, particularly in long-term marriages where circumstances have changed substantially. Courts are more likely to enforce support waivers in short-term childless marriages than in marriages lasting 20 or 30 years where one spouse became financially dependent.

Retirement accounts, including 401(k) plans, IRAs, pensions, and profit-sharing plans, can be addressed in Michigan prenuptial agreements to clarify whether contributions and appreciation during marriage will be treated as separate or marital property. The agreement can specify that each party retains sole ownership of their pre-marital retirement accounts and all appreciation, even if the appreciation occurred during marriage. Alternatively, the prenup can establish a formula for dividing retirement benefits based on the duration of marriage or other factors. Michigan law allows prenuptial agreements to waive rights to survivor benefits and community property rights in retirement accounts, but these waivers must comply with federal ERISA requirements for qualified retirement plans. Business owners can use prenuptial agreements to protect business interests by specifying that the business remains separate property and that the non-owner spouse has no claim to business assets, income, or appreciation during marriage.

Debt allocation provisions in Michigan prenuptial agreements establish which party will be responsible for specific debts in the event of divorce. The agreement can specify that each party remains solely responsible for debts incurred before marriage, student loans, business debts, credit card balances, and other obligations. However, debt allocation provisions in prenuptial agreements only bind the spouses and do not affect creditor rights, meaning a creditor can still pursue either spouse for joint debts regardless of what the prenup states. Attorney's fees provisions can specify which party will pay legal costs if the prenuptial agreement is challenged in court or if the parties divorce. Michigan law permits prenuptial agreements to include provisions for estate planning, such as waiving inheritance rights, defining the disposition of property upon death, and establishing life insurance requirements.

What Cannot Be Included in Michigan Prenuptial Agreements

Child custody and parenting time arrangements cannot be predetermined in Michigan prenuptial agreements because courts must determine custody based on the best interests of the child at the time of divorce under MCL § 722.23. The best interest factors include the love and affection between the child and each parent, the capacity of each parent to provide guidance and education, the permanence of the family unit, the moral fitness of the parties, the mental and physical health of the parties, the child's home environment, and the child's reasonable preference. These factors can only be evaluated when divorce occurs, not years earlier when a prenuptial agreement is signed. Any prenuptial agreement provisions attempting to specify custody arrangements, parenting time schedules, or decision-making authority will be deemed unenforceable and void as against public policy.

Child support obligations cannot be waived or limited in Michigan prenuptial agreements because child support is the right of the child, not the parent, and parents cannot bargain away their children's rights. Michigan child support is calculated using the Michigan Child Support Formula established in the Michigan Child Support Formula Manual, which considers the income of both parents, number of children, overnight parenting time, childcare costs, and healthcare expenses. MCL § 552.605 requires courts to calculate child support using the formula unless deviation is in the child's best interests. Parents have an obligation to support their children regardless of any agreement between themselves, and courts will disregard any prenuptial provisions attempting to limit or eliminate child support obligations.

Provisions that promote divorce or provide financial incentives for ending the marriage are unenforceable in Michigan prenuptial agreements as contrary to public policy. Michigan courts have long recognized that marriage is a fundamental institution that should not be undermined by contractual provisions making divorce financially advantageous. For example, a clause stating that one party receives $1 million if the marriage ends within five years would be void because it incentivizes divorce. Similarly, provisions that penalize one party for filing for divorce, such as forfeiting all marital property rights if they initiate divorce proceedings, are also unenforceable. Michigan law permits prenuptial agreements to address the financial consequences of divorce but not to encourage or discourage the decision to divorce itself.

Unconcionable provisions or terms that are grossly unfair or one-sided at the time of enforcement cannot be included in Michigan prenuptial agreements. While a prenup may have been fair when signed, if circumstances change substantially during the marriage such that enforcement would leave one spouse destitute or without means of support, Michigan courts will refuse to enforce the unconscionable terms. For example, if a prenuptial agreement waives all spousal support rights but one spouse later becomes disabled and unable to work while the other spouse earns substantial income, the court may award support despite the waiver. Michigan courts evaluate unconscionability at the time of divorce, not at the time of signing, which means couples should include provisions allowing for modification if circumstances change substantially.

Requirements for a Valid and Enforceable Michigan Prenuptial Agreement

Full financial disclosure is the most critical requirement for an enforceable Michigan prenuptial agreement. Both parties must fully disclose all assets and their values, all debts and liabilities, all income sources and amounts, education and employment history, age and health status, and any other material facts affecting financial circumstances. Michigan requires a special duty of full disclosure that exceeds the ordinary due diligence requirements in commercial contracts because of the confidential relationship between prospective spouses. Failure to disclose significant assets or debts, even if the other party did not specifically ask about them, can render the entire agreement unenforceable. Michigan courts have held that full disclosure means each party is fully aware of the other party's financial situation and has access to complete information necessary to make an informed decision about signing the agreement.

Voluntary execution without fraud, duress, or undue influence is essential for prenuptial agreement enforceability in Michigan. The agreement must be entered into freely by both parties with a full understanding of their rights and the legal consequences of waiving those rights. Duress exists when one party was forced or pressured to sign the agreement under circumstances that overcame their free will, such as threats of calling off the wedding if they refuse to sign, pressure to sign immediately before the wedding ceremony without time for review, refusal to allow the other party to consult with independent legal counsel, or emotional manipulation or coercion. Michigan courts scrutinize the circumstances surrounding execution and will void agreements signed under pressure, even if there was technical compliance with other requirements. The timing of presenting the prenuptial agreement matters significantly, as courts are more likely to find voluntariness when the agreement was presented months before the wedding rather than days or hours before.

Written form and notarization requirements under MCL § 557.28 mandate that prenuptial agreements must be in writing, signed by both parties, and properly notarized to be enforceable. Oral prenuptial agreements are completely invalid in Michigan and cannot be enforced under any circumstances. The written agreement must clearly identify both parties, state that it is a prenuptial agreement made in contemplation of marriage, specify the effective date (typically the date of marriage), contain all material terms regarding property and support rights, and include signatures of both parties before a notary public. Notarization serves as evidence that the parties personally appeared, acknowledged signing the document, and did so voluntarily. While Michigan law does not require each party to have independent legal representation for the agreement to be valid, having separate attorneys significantly strengthens the presumption of voluntariness and understanding.

Fairness and lack of unconscionability at the time of execution and enforcement are required for Michigan prenuptial agreements to be upheld. The agreement must be fair, equitable, and reasonable under the circumstances when signed and cannot be unconscionable when enforced at the time of divorce. Michigan courts evaluate unconscionability using a two-part test: substantive unconscionability (whether the terms are unreasonably favorable to one party) and procedural unconscionability (whether the bargaining process was unfair). An agreement is substantively unconscionable if it leaves one party without sufficient assets or income for basic needs while the other party retains substantial wealth. Procedural unconscionability exists when one party lacked meaningful choice due to lack of legal representation, insufficient time to review, lack of disclosure, or disparity in sophistication between the parties. Michigan courts are more likely to find agreements unconscionable in long-term marriages where circumstances changed substantially since execution.

Average Cost of a Prenuptial Agreement in Michigan

Attorney fees for drafting Michigan prenuptial agreements average $750 to $2,400 based on marketplace data as of March 2026. The cost varies significantly based on the complexity of assets, whether the couple has children from prior relationships, the level of negotiation required, and the experience level of the attorney. Simple prenuptial agreements for young couples with limited assets and no children may cost $750 to $1,200, while complex agreements involving business ownership, multiple properties, substantial investment portfolios, or intricate spousal support provisions can cost $2,400 to $5,000 or more. Michigan family law attorneys typically charge hourly rates ranging from $200 to $350 per hour for prenuptial agreement services, with more experienced attorneys in metropolitan areas like Detroit, Grand Rapids, and Ann Arbor charging at the higher end of this range.

Each party should retain separate independent legal counsel when entering into a prenuptial agreement to ensure their interests are adequately protected and to strengthen the enforceability of the agreement. The cost of having two attorneys involved typically ranges from $1,500 to $4,800 combined. While Michigan law does not mandate separate representation for prenuptial agreements to be valid, courts give significant weight to whether each party had the opportunity to consult with their own lawyer. Having independent counsel makes it much more difficult for a party to later claim they did not understand the agreement, were pressured into signing, or that the terms were unconscionable. The additional cost of separate attorneys is worthwhile considering that a properly executed prenuptial agreement can protect assets worth hundreds of thousands or millions of dollars.

Additional costs associated with Michigan prenuptial agreements include notary fees of $10 to $25 per signature, financial disclosure document preparation fees if you need an accountant to prepare detailed asset valuations, business valuation costs if the prenup involves a closely held business, and potential court filing fees only if the agreement is later contested during divorce proceedings. Michigan does not require prenuptial agreements to be filed with any court or government agency before marriage, so there are no mandatory filing fees. The agreement is a private contract between the parties that becomes relevant only if the parties later divorce and one party seeks to enforce or challenge its terms. Keep all original documents and executed copies in a secure location, as you will need them if divorce occurs.

How Michigan Courts Evaluate Prenuptial Agreements During Divorce

Michigan courts apply a multi-factor analysis when evaluating whether to enforce prenuptial agreements during divorce proceedings under MCL § 552.401 and MCL § 552.23. The court first examines whether the agreement meets the formal requirements of MCL § 557.28: written form, signatures of both parties, and proper notarization. If these threshold requirements are not met, the prenuptial agreement is void and unenforceable. If the formal requirements are satisfied, the court proceeds to evaluate whether the agreement was voluntarily executed with full disclosure and whether enforcement would be unconscionable based on current circumstances. The party challenging the prenuptial agreement bears the burden of proving invalidity by clear and convincing evidence, which is a higher standard than the preponderance of evidence used in most civil matters.

The voluntariness inquiry focuses on the circumstances surrounding execution, including the timing of when the agreement was presented, whether each party had opportunity to consult independent legal counsel, the level of sophistication and bargaining power of each party, and whether there were threats or pressure to sign. Michigan courts have found prenuptial agreements involuntary when presented 24 to 48 hours before the wedding ceremony, when one party was significantly more educated or financially sophisticated than the other and the less sophisticated party had no attorney, or when one party threatened to cancel the wedding or end the relationship if the other refused to sign. Courts presume voluntariness when the agreement was presented several months before the wedding, each party was represented by independent counsel, and both parties had adequate time to review and negotiate the terms.

Full disclosure evaluation examines whether each party provided complete information about assets, debts, income, and financial circumstances before signing. Michigan courts require disclosure of all material facts that could affect the other party's decision to enter into the agreement, including the existence and approximate value of real property, business interests, investment accounts, retirement plans, bank accounts, vehicles, personal property of significant value, debts and liabilities, and current income from all sources. Courts will void prenuptial agreements when one party concealed assets, significantly undervalued assets, failed to disclose debts, or misrepresented income. The fact that the other party could have conducted independent investigation does not excuse failure to disclose because Michigan law imposes an affirmative duty of disclosure on both parties in prenuptial agreements.

Unconscionability analysis considers whether enforcement of the prenuptial agreement would be manifestly unfair based on circumstances at the time of divorce. Michigan courts evaluate unconscionability differently than many states because they consider both the circumstances at execution and the circumstances at the time of divorce. Factors courts examine include the length of the marriage (agreements in marriages lasting 20 or 30 years face greater scrutiny), whether circumstances changed substantially since execution (such as disability, job loss, or caretaking responsibilities), whether enforcement would leave one party destitute while the other retains substantial assets, the relative age and health of the parties at the time of divorce, and whether one party sacrificed career opportunities to support the family or the other spouse's career. Courts are particularly reluctant to enforce spousal support waivers in long-term marriages where one spouse stayed home to raise children while the other advanced professionally.

Modifying or Revoking a Michigan Prenuptial Agreement

Michigan prenuptial agreements can be modified or revoked by mutual written agreement of both parties at any time before or during the marriage. MCL § 557.28 applies the same formal requirements to modifications as to the original agreement: the modification must be in writing, signed by both parties, and notarized to be enforceable. Oral agreements to modify or revoke a prenuptial agreement are not valid in Michigan and cannot be enforced, even if both parties agree that they made such an agreement. Any modification should be drafted by an attorney to ensure it complies with Michigan law and clearly states which provisions of the original agreement are being changed, added, or deleted. The modification becomes part of the prenuptial agreement and will be evaluated using the same standards of voluntariness, full disclosure, and conscionability if later challenged in divorce proceedings.

Automatic revocation upon divorce or death does not occur in Michigan unless the prenuptial agreement specifically includes such a provision. Most prenuptial agreements are intended to govern the parties' rights in the event of divorce or death, so they remain in effect unless affirmatively modified or revoked. However, parties can include sunset clauses that automatically terminate the agreement after a specified number of years of marriage, milestone clauses that modify terms upon certain events like the birth of children, or automatic escalation provisions that increase support obligations the longer the marriage lasts. These provisions must be clearly stated in the original agreement or in a written modification. Michigan courts enforce sunset and milestone provisions if they were voluntarily agreed to and the terms are clear and unambiguous.

Postnuptial agreements, which are entered into after marriage rather than before, are treated differently than prenuptial agreements in Michigan. The Michigan Supreme Court has held that postnuptial agreements require additional scrutiny because the parties are already married and owe each other fiduciary duties. Michigan law regarding postnuptial agreements is currently in a state of flux, with courts applying heightened standards for enforceability. Postnuptial agreements must meet the same formal requirements as prenuptial agreements (written, signed, notarized) but face additional requirements of consideration (something of value exchanged for the agreement), fair dealing between parties with fiduciary duties to each other, and absence of coercion or overreaching. Courts are more likely to find postnuptial agreements unconscionable or involuntary than prenuptial agreements because of the changed power dynamics after marriage.

Challenging a prenuptial agreement during divorce requires the challenging party to prove by clear and convincing evidence that the agreement is invalid due to failure to meet formal requirements, lack of full disclosure, involuntariness or duress, unconscionability at execution or enforcement, fraud or misrepresentation, or lack of mental capacity when signed. The challenging party must present specific evidence, not merely general allegations, supporting their claims. Evidence may include testimony about the circumstances of signing, financial documents showing lack of disclosure, expert testimony about asset values or the sophistication of the parties, and documentary evidence of threats or pressure. Michigan courts disfavor challenges to prenuptial agreements and will enforce valid agreements even if the terms favor one party, as long as the procedural safeguards of voluntariness and full disclosure were satisfied.

Prenuptial Agreements vs. Postnuptial Agreements in Michigan

Prenuptial agreements are executed before marriage in contemplation of the upcoming wedding, while postnuptial agreements are executed after the marriage has already occurred. The timing distinction is legally significant in Michigan because prenuptial agreements are governed by MCL § 557.28, which requires only that the agreement be in writing and made in contemplation of marriage, while postnuptial agreements are subject to general contract law principles plus the additional requirement of valid consideration. Consideration means that each party must receive something of value in exchange for signing the agreement. In a prenuptial agreement, the mutual promises to marry constitute sufficient consideration, but in a postnuptial agreement, the parties are already married, so additional consideration is required, such as the promise to remain married rather than divorce immediately, the exchange of property rights beyond what would occur in divorce, or the resolution of existing marital disputes.

Michigan courts apply heightened scrutiny to postnuptial agreements because married spouses owe each other fiduciary duties of trust, confidence, and good faith that do not exist between unmarried persons negotiating a prenuptial agreement. The Michigan Supreme Court has held that postnuptial agreements are subject to closer examination than prenuptial agreements due to the confidential relationship that exists between spouses. This means that postnuptial agreements face a lower threshold for being found unconscionable, require more extensive disclosure of assets and financial circumstances, face greater scrutiny regarding voluntariness and whether one spouse took advantage of the other, and are more likely to be modified or set aside if circumstances change during the marriage. Michigan law regarding postnuptial agreements is currently less settled than prenuptial agreement law, and courts have greater discretion to refuse enforcement when they believe doing so would be inequitable.

Practical differences between prenuptial and postnuptial agreements affect when each type of agreement is appropriate. Prenuptial agreements are typically used by couples planning to marry who want to protect assets acquired before marriage, clarify property rights before combining finances, address concerns about business ownership or professional practice interests, or establish expectations about financial responsibilities during marriage. Postnuptial agreements are more commonly used when circumstances have changed since marriage, such as receipt of a large inheritance or gift during marriage, start of a new business during marriage, significant change in income or financial circumstances, reconciliation after separation or infidelity, or to address disputes about money management or spending during marriage. Both types of agreements must meet Michigan's requirements of written form, signatures of both parties, notarization, full disclosure, voluntariness, and lack of unconscionability.

How to Create an Enforceable Prenuptial Agreement in Michigan

Start the prenuptial agreement process at least three to six months before your wedding date to avoid claims of duress or pressure. Michigan courts scrutinize agreements signed close to the wedding date because one party may feel unable to back out due to venue deposits, travel arrangements for guests, and social pressure. Beginning discussions well in advance demonstrates that both parties entered into the agreement voluntarily with adequate time for consideration, consultation with independent counsel, and negotiation of terms. Use this timeline to gather financial documents, meet with attorneys, draft and review the agreement, negotiate any changes, and finalize and execute the agreement with sufficient buffer time before the wedding.

Retain separate independent legal counsel for each party to represent their individual interests and ensure the prenuptial agreement is enforceable. While Michigan law does not require separate attorneys for validity, having independent representation creates a strong presumption of voluntariness and understanding that makes challenges to the agreement much more difficult. Each attorney can advise their client about Michigan law on property division and spousal support, review the proposed terms for fairness and enforceability, negotiate provisions to protect their client's interests, ensure full disclosure of assets and debts, and explain the legal rights being waived by signing the agreement. The cost of two attorneys is worthwhile considering that a properly drafted prenuptial agreement can protect substantial assets and avoid expensive litigation if divorce occurs.

Prepare complete financial disclosure documents listing all assets, debts, income sources, and relevant financial information for both parties. Michigan requires full disclosure, so gather documentation including recent bank statements, investment account statements, retirement account statements, real property deeds and recent appraisals, business financial statements and valuations, vehicle titles and values, credit card statements showing current balances, loan documents for mortgages and other debts, tax returns for the past two to three years, and pay stubs or other proof of current income. Each party should sign a financial disclosure affidavit stating that they have provided complete and accurate information about their financial circumstances and have reviewed the other party's disclosure documents. Attach copies of supporting documentation to the affidavit to create a complete record that can be referenced if the agreement is later challenged.

Draft clear and unambiguous terms that specifically address property division rules for separate property and marital property, spousal support provisions including whether support can be awarded and any limitations or waivers, retirement account treatment and division formulas, business ownership and valuation methods if applicable, debt allocation and responsibility for pre-marital and marital debts, estate planning provisions including inheritance rights and life insurance, and procedures for modifying the agreement and resolving disputes. Avoid vague language like "fair share" or "reasonable amount" and instead use specific formulas, dollar amounts, or objective criteria. Include provisions addressing potential future changes like the birth of children, significant increases in income or assets, disability or loss of employment, or other circumstances that could affect the fairness of the original terms.

Execute the prenuptial agreement with proper formalities by having both parties sign in the presence of a notary public, ensuring each party has had adequate time to review the final document, confirming that both parties understand the terms and legal consequences, and obtaining multiple original executed copies for each party and their attorneys. Do not present the final agreement for signing at the last minute before the wedding. The agreement should be fully negotiated and in final form at least 30 days before the wedding, with execution occurring at least two weeks before the ceremony. Store original executed copies in a secure location along with all financial disclosure documents, as you will need these materials if divorce occurs and one party seeks to enforce or challenge the prenuptial agreement.

Common Mistakes to Avoid with Michigan Prenuptial Agreements

Waiting until shortly before the wedding to present a prenuptial agreement is one of the most common mistakes that leads to unenforceability. Michigan courts have voided agreements signed 24 to 48 hours before the wedding ceremony because the other party had insufficient time to review the terms, consult with an attorney, and make a voluntary decision about whether to sign. The closer to the wedding date the agreement is presented, the more pressure the other party feels to sign because of venue deposits, guest travel arrangements, and social embarrassment of canceling the wedding. Courts recognize that this pressure undermines voluntariness even if there are no explicit threats. Present the prenuptial agreement at least three to six months before the wedding to demonstrate good faith and allow adequate time for negotiation.

Failing to provide full financial disclosure is a critical error that will invalidate the entire prenuptial agreement in Michigan. Some people mistakenly believe they only need to disclose assets or income if specifically asked about them, but Michigan law requires affirmative disclosure of all material financial information without waiting to be asked. Concealing assets, even if the other party could have discovered them through independent investigation, violates the duty of disclosure. Significantly undervaluing assets in disclosure documents also constitutes failure to provide full disclosure. Both parties should prepare detailed financial disclosure affidavits listing all assets with reasonable valuations, all debts and liabilities, all income sources and amounts, and any other material facts affecting financial circumstances, and attach supporting documentation like bank statements and tax returns.

Including unenforceable provisions about child custody, parenting time, or child support creates problems even if other provisions of the prenuptial agreement are valid. Michigan law is clear that these matters cannot be predetermined because courts must evaluate custody based on the best interests of the child at the time of divorce under MCL § 722.23 and must calculate child support using the Michigan Child Support Formula under MCL § 552.605. While some courts will sever invalid provisions and enforce the remainder of the agreement, other courts may void the entire agreement if it contains provisions attempting to waive children's rights. Limit prenuptial agreements to matters the parties can legally contract about: property division, spousal support, attorney's fees, and estate planning provisions.

Drafting overly one-sided terms that provide nearly all assets to one party and waive all support rights of the other party increases the risk that Michigan courts will find the agreement unconscionable and refuse enforcement. While prenuptial agreements do not need to be equal or perfectly fair, they cannot be so imbalanced that enforcement would leave one party destitute while the other retains substantial wealth. Consider including provisions that increase support obligations or property division percentages based on the length of marriage, such as gradually increasing spousal support from zero for marriages under five years to a percentage of income for longer marriages. Build in protections for circumstances that could make strict enforcement unconscionable, such as disability, unemployment, or caregiving responsibilities for children or elderly parents. Courts are more likely to enforce agreements that demonstrate consideration of potential future circumstances rather than rigid one-sided terms.

Using online templates or DIY prenuptial agreement forms without attorney review is a false economy that often results in unenforceable agreements or provisions that do not accomplish the intended goals. Generic templates cannot account for Michigan-specific legal requirements, may use language from other states that conflicts with Michigan law, often include provisions that are unenforceable in Michigan, and typically fail to address the specific circumstances and assets of the parties. The cost of hiring an attorney to draft or review a prenuptial agreement, typically $750 to $2,400 in Michigan, is minimal compared to the value of assets being protected and the cost of litigation if the agreement is later challenged. Investing in proper legal representation when creating the prenuptial agreement provides peace of mind and dramatically increases the likelihood of enforcement if divorce occurs.

Frequently Asked Questions About Michigan Prenuptial Agreements

Do prenuptial agreements expire in Michigan?

Michigan prenuptial agreements remain valid indefinitely unless they include a specific sunset clause stating that the agreement expires after a certain number of years of marriage or upon the occurrence of specified events. MCL § 557.28 states that prenuptial agreements remain in full force after marriage takes place without any automatic expiration. However, courts evaluate whether enforcement would be unconscionable based on circumstances at the time of divorce, so agreements signed many years ago may be modified or refused enforcement if circumstances have changed substantially during a long-term marriage.

Can a prenuptial agreement protect my business in Michigan?

Yes, Michigan prenuptial agreements can protect business interests by specifying that the business remains separate property not subject to division in divorce and that any appreciation in business value during marriage remains separate property. The agreement should clearly identify the business, state its approximate current value, specify that the non-owner spouse waives all claims to business assets and income, and establish a valuation method if any compensation is required for the non-owner spouse's contributions. Business owners should provide full disclosure of business financials when executing the prenuptial agreement to avoid later claims of inadequate disclosure.

How much does a prenuptial agreement cost in Michigan?

The average cost of a Michigan prenuptial agreement ranges from $750 to $2,400 for attorney fees as of March 2026, with complex agreements involving business interests or substantial assets costing $3,000 to $5,000 or more. Each party should retain separate legal counsel, so the combined cost typically ranges from $1,500 to $4,800 when both attorneys' fees are included. Michigan family law attorneys charge hourly rates of $200 to $350 per hour for prenuptial agreement services, with total costs depending on the complexity of assets, level of negotiation required, and time spent drafting and reviewing the agreement.

Can I modify my prenuptial agreement after marriage?

Yes, Michigan prenuptial agreements can be modified at any time by mutual written agreement of both parties. The modification must meet the same formal requirements as the original prenuptial agreement under MCL § 557.28: written form, signatures of both parties, and notarization. Oral agreements to modify a prenuptial agreement are not enforceable in Michigan. The modification should clearly state which provisions are being changed and should be drafted by an attorney to ensure compliance with Michigan law and enforceability in the event of divorce.

Are prenups enforceable if we divorce after 20 years?

Michigan courts generally enforce valid prenuptial agreements in long-term marriages, but they exercise greater scrutiny to ensure enforcement is not unconscionable based on changes in circumstances since execution. Courts are more likely to modify or refuse enforcement in marriages lasting 20 or 30 years where one spouse sacrificed career opportunities to raise children or support the other spouse's career, developed a disability or health condition that prevents work, or would be left without adequate means of support while the other spouse retains substantial assets. Including provisions that adjust terms based on length of marriage increases enforceability in long-term marriages.

Can a prenup waive all spousal support in Michigan?

Yes, Michigan prenuptial agreements can waive spousal support rights, but such waivers are subject to court review under MCL § 552.23(1) and MCL § 552.401 to ensure enforcement is not unconscionable. Courts generally enforce support waivers when the agreement was properly executed with full disclosure and voluntariness, the marriage is relatively short in duration, and both parties remain financially self-sufficient. However, courts are more likely to award support despite a waiver in long-term marriages, when one spouse becomes disabled or unable to work, or when enforcement would leave one spouse without adequate means of support while the other retains substantial wealth.

What happens if we move to another state after signing a Michigan prenup?

Michigan prenuptial agreements remain enforceable if you later move to another state and divorce there, but the courts of your new state of residence will apply that state's law to evaluate enforceability. Most states recognize and enforce valid prenuptial agreements from other states under principles of comity and full faith and credit, but each state has its own standards for what makes an agreement valid and enforceable. If you move to a state with substantially different laws, consider having an attorney in your new state review the agreement and potentially execute a modification or new agreement that complies with the new state's requirements.

Do both parties need separate attorneys for a prenup to be valid in Michigan?

No, Michigan law does not require each party to have independent legal counsel for a prenuptial agreement to be valid and enforceable under MCL § 557.28. However, having separate attorneys creates a strong presumption of voluntariness and understanding that makes later challenges much more difficult. Courts give significant weight to whether each party had the opportunity to consult with their own lawyer who could explain Michigan law, review the proposed terms for fairness, and negotiate provisions to protect their client's interests. The cost of separate representation is worthwhile considering the assets at stake.

Can a prenuptial agreement address inheritance rights in Michigan?

Yes, Michigan prenuptial agreements can include estate planning provisions that waive inheritance rights, specify the disposition of property upon death, establish life insurance requirements, and determine whether spousal election rights against a will are waived. These provisions are enforceable if the agreement was properly executed with full disclosure and voluntariness. However, prenuptial agreements addressing inheritance rights should be coordinated with formal estate planning documents like wills and trusts to ensure consistency. Consult with both a family law attorney and an estate planning attorney when including inheritance provisions in a prenuptial agreement.

What should I do if my fiancé refuses to sign a prenuptial agreement?

If your fiancé refuses to sign a prenuptial agreement, you must decide whether to proceed with the marriage without the protections the agreement would provide or postpone or cancel the wedding until the issue is resolved. You cannot force someone to sign a prenuptial agreement, and attempting to do so through threats or pressure would make any resulting agreement unenforceable due to duress. Consider discussing your concerns openly, explaining why the prenuptial agreement is important to you, addressing any misconceptions about what prenuptial agreements mean for the relationship, and offering to negotiate terms that address both parties' concerns rather than presenting a take-it-or-leave-it agreement. If you cannot reach agreement, seek premarital counseling to discuss financial expectations and concerns before marriage.

This guide was authored by Antonio G. Jimenez, Esq., Florida Bar No. 21022, covering Michigan divorce law. Content verified as of March 2026. While Attorney Jimenez is licensed to practice law in Florida, this article provides educational information about Michigan law only and does not constitute legal advice. For specific legal guidance about your situation, consult a Michigan-licensed family law attorney.

Sources:

• Michigan Legislature - MCL 557.28
• Kelly Kelly Law - Antenuptial Agreements in Michigan
• ContractsCounsel - Michigan Prenuptial Agreement Cost
• Kreis Enderle - Prenuptial Agreement Enforceability
• Michigan Legislature - Senate Bill 160
• Oakland County Family Law - Prenuptial Agreements
• Michigan Courts - Equitable Distribution