Illinois uses a statutory formula to calculate spousal maintenance (alimony): 33.33% of the payor's net income minus 25% of the payee's net income, capped so the recipient receives no more than 40% of combined net income. This formula applies when combined gross income falls below $500,000 under 750 ILCS 5/504. Duration depends on marriage length, ranging from 20% of the marriage duration for marriages under 5 years to indefinite maintenance for marriages lasting 20 or more years. Filing for divorce in Illinois costs $210 to $388 depending on county, and at least one spouse must have resided in the state for 90 consecutive days before filing.
Antonio G. Jimenez, Esq. | Florida Bar No. 21022 | Covering Illinois divorce law
Key Facts: Illinois Spousal Maintenance at a Glance
| Category | Details |
|---|---|
| Governing Statute | 750 ILCS 5/504 — Illinois Marriage and Dissolution of Marriage Act |
| Filing Fee | $210 to $388 depending on county (as of March 2026) |
| Waiting Period | None for maintenance; divorce requires irreconcilable differences |
| Residency Requirement | 90 consecutive days for at least one spouse (750 ILCS 5/401(a)) |
| Grounds for Divorce | No-fault only — irreconcilable differences |
| Property Division | Equitable distribution (not 50/50) |
| Formula Income Cap | $500,000 combined gross annual income |
| Maintenance Formula | 33.33% of payor's net income minus 25% of payee's net income |
| Maximum Award Cap | Recipient cannot receive more than 40% of combined net income |
| Tax Treatment | Not deductible by payor; not taxable to recipient (post-TCJA) |
How Does the Illinois Alimony Calculator Formula Work?
Illinois calculates spousal maintenance using a precise statutory formula set forth in 750 ILCS 5/504(b-1): the court takes 33.33% of the payor's net income and subtracts 25% of the payee's net income. The resulting amount cannot push the payee's total income above 40% of the combined net income of both spouses. This formula applies only when combined gross annual income is below $500,000.
Step-by-Step Calculation
To use an alimony calculator for Illinois, follow these steps:
- Determine each spouse's net annual income (gross income minus taxes, Social Security, and mandatory deductions)
- Multiply the higher-earning spouse's net income by 0.3333 (33.33%)
- Multiply the lower-earning spouse's net income by 0.25 (25%)
- Subtract the result from Step 3 from the result in Step 2
- Add the Step 4 amount to the payee's net income
- Compare that total to 40% of the combined net income
- The maintenance amount is the lesser of the Step 4 result or the amount that brings the payee to the 40% cap
Example Calculation
Consider a couple where the payor earns $120,000 net annually and the payee earns $40,000 net annually:
- 33.33% of $120,000 = $39,996
- 25% of $40,000 = $10,000
- Guideline maintenance = $39,996 minus $10,000 = $29,996 per year ($2,500 per month)
- 40% cap check: Combined net income = $160,000. The 40% cap = $64,000. Payee's income plus maintenance = $40,000 + $29,996 = $69,996. This exceeds $64,000, so the cap applies.
- Capped maintenance = $64,000 minus $40,000 = $24,000 per year ($2,000 per month)
The court would award $2,000 per month in this scenario, not $2,500, because the 40% cap limits the total amount the payee can receive.
How Long Does Spousal Maintenance Last in Illinois?
Illinois determines maintenance duration by multiplying the length of the marriage by a statutory factor outlined in 750 ILCS 5/504(b-1). A 10-year marriage results in a maintenance period of 4 years (10 multiplied by 0.40), while a marriage lasting 20 or more years may result in indefinite maintenance at the court's discretion.
| Marriage Duration | Duration Multiplier | Example: Maintenance Period |
|---|---|---|
| 0 to 5 years | 0.20 (20%) | 4-year marriage = 0.8 years (about 10 months) |
| 5 to 10 years | 0.40 (40%) | 8-year marriage = 3.2 years |
| 10 to 15 years | 0.60 (60%) | 12-year marriage = 7.2 years |
| 15 to 20 years | 0.80 (80%) | 18-year marriage = 14.4 years |
| 20 or more years | 1.00 (100%) or indefinite | 25-year marriage = 25 years or permanent |
For marriages lasting 20 or more years, 750 ILCS 5/504(b-1) gives the court authority to order maintenance for a period equal to the full length of the marriage or for an indefinite term. Courts consider the recipient's age, health, and realistic employment prospects when deciding between fixed-term and indefinite awards in long-duration marriages.
What Types of Spousal Maintenance Exist in Illinois?
Illinois courts may award four distinct types of spousal maintenance under 750 ILCS 5/504: temporary, fixed-term, reviewable, and indefinite. The court must designate the type in every maintenance order, and each type carries different modification and termination rules that affect both the payor's obligations and the recipient's planning horizon.
| Type | Description | When Used |
|---|---|---|
| Temporary | Awarded during the divorce proceedings before final judgment | Spouse needs immediate financial support while case is pending |
| Fixed-Term | Set for a specific period; maintenance is barred after expiration | Shorter marriages; payee expected to become self-supporting |
| Reviewable | Set for a specific term with court review at expiration | Uncertain whether payee will become self-supporting |
| Indefinite | No termination date; continues until modification or triggering event | Marriages of 20+ years; payee unlikely to achieve self-sufficiency |
Temporary maintenance uses the same 33.33%-minus-25% formula as permanent maintenance. Fixed-term maintenance ends automatically on the designated date, and the recipient cannot petition for extension after expiration. Reviewable maintenance allows the court to reassess the recipient's circumstances and either extend, reduce, or terminate the award at the review date. Indefinite maintenance continues until death of either party, remarriage of the recipient, or cohabitation on a continuing conjugal basis under 750 ILCS 5/510(c).
What Factors Do Illinois Courts Consider When Awarding Maintenance?
Illinois courts evaluate 14 statutory factors under 750 ILCS 5/504(a) before determining whether maintenance is appropriate and applying the formula. These factors include each party's income and property, realistic earning capacity, standard of living during the marriage, and contributions to the other spouse's education or career advancement.
The 14 factors courts must weigh are:
- Income and property of each party, including marital property apportioned in the divorce and non-marital property assigned to each spouse
- Needs of each party based on the standard of living established during the marriage
- Present and future earning capacity of each party, assessed realistically
- Impairment of the maintenance-seeking party's earning capacity due to time devoted to domestic duties or delayed education
- Impairment of the payor's earning capacity if maintenance is ordered
- Time necessary for the recipient to acquire sufficient education, training, and employment
- Standard of living established during the marriage
- Duration of the marriage
- Age, health, station, occupation, income sources, vocational skills, employability, estate, liabilities, and needs of each party
- All sources of public and private income, including disability and retirement benefits
- Tax consequences of the property division upon each party's economic circumstances
- Contributions and services by the maintenance-seeking party to the education, training, career, or professional license of the other spouse
- Any valid agreement between the parties regarding maintenance
- Any other factor the court expressly finds to be just and equitable
Courts are not required to give equal weight to each factor. A spouse who sacrificed a career to raise children for 15 years will receive greater weight on factors 4, 6, and 12 than a spouse in a 3-year marriage where both parties worked full-time throughout.
How Do Filing Fees and Court Costs Affect the Alimony Process in Illinois?
Filing for divorce in Illinois costs between $210 and $388 depending on the county, with Cook County charging the highest rate of $388 for the initial petition. The respondent's appearance fee ranges from $218 to $251. Fee waivers are available for parties who demonstrate financial hardship through standardized Illinois Supreme Court forms. As of March 2026. Verify with your local clerk.
| County | Petition Filing Fee | Appearance Fee |
|---|---|---|
| Cook County | $388 | $251 |
| DuPage County | $337 to $348 | $218 |
| Kane County | $295 | Varies |
| Other Illinois counties | $210 to $320 | Varies |
Beyond filing fees, contested divorce cases involving spousal maintenance disputes typically cost $15,000 to $30,000 or more in attorney fees in Illinois. Uncontested divorces where both parties agree on maintenance terms may cost $3,000 to $5,000 in total legal fees. These costs are separate from the maintenance payments themselves. Under 750 ILCS 5/508, the court may order one spouse to contribute to the other's attorney fees if there is a significant income disparity.
When Does the Formula Not Apply? High-Income and Non-Guideline Cases
The Illinois maintenance formula does not apply when the parties' combined gross annual income exceeds $500,000 under 750 ILCS 5/504(b-1). In high-income cases, the court exercises full discretion over both the amount and duration of maintenance, weighing the 14 statutory factors without any mathematical formula constraint. The formula also does not apply if the payor already has a maintenance or child support obligation from a prior relationship.
In non-guideline cases above the $500,000 threshold, courts often look to the marital standard of living as the primary benchmark. A couple earning a combined $800,000 annually with a 15-year marriage will not be bound by the 33.33%-minus-25% calculation. Instead, the court examines housing costs, travel patterns, education expenses, and lifestyle expectations to determine an appropriate maintenance award. Judges retain authority to deviate from the formula in any case where applying it would be inequitable, though deviations below $500,000 require the court to state specific reasons on the record.
How Do Taxes Affect Spousal Maintenance Payments in Illinois?
Spousal maintenance payments in Illinois are not tax-deductible for the payor and not taxable income for the recipient for any divorce finalized after December 31, 2018, under the Tax Cuts and Jobs Act of 2017 (Public Law 115-97). This federal tax change is permanent and does not expire when other TCJA provisions sunset. Illinois updated its maintenance formula from gross income to net income in 2019 (via SB 2289) specifically to account for the elimination of the tax deduction.
The shift from gross to net income in the Illinois formula means the alimony calculator produces lower nominal amounts than pre-2019 calculations but reflects the actual financial impact more accurately. Before 2019, a payor earning $150,000 gross would pay maintenance calculated on gross income but could deduct the payments from taxable income. Now the calculation uses net income, producing a smaller number that the payor cannot deduct. For divorces finalized before January 1, 2019, the old tax treatment (deductible to payor, taxable to recipient) still applies unless the parties later modify the agreement to adopt TCJA treatment.
What Recent Law Changes Affect Illinois Maintenance in 2025 and 2026?
Public Act 103-0967, effective January 1, 2025, changed how Illinois handles maintenance during incarceration. Under the new law, spousal maintenance payments continue to accrue as arrears when the payor is incarcerated, rather than being automatically suspended. The incarcerated party must petition the court for a modification rather than relying on automatic suspension of the obligation.
This change means a payor who is incarcerated for 2 years will owe 2 years of accumulated maintenance arrears upon release unless they successfully petition for modification during the incarceration period. Prior to this change, some Illinois courts automatically paused maintenance obligations during incarceration. The existing termination triggers remain unchanged: maintenance ends upon death of either party, remarriage of the recipient, or cohabitation on a continuing conjugal basis under 750 ILCS 5/510(c). No additional changes to the maintenance formula or duration multipliers have been enacted for 2026.
What Are the Residency Requirements for Filing for Divorce in Illinois?
At least one spouse must have been a resident of Illinois for 90 consecutive days immediately before filing for divorce under 750 ILCS 5/401(a). Either spouse can satisfy this requirement; both parties do not need to live in Illinois. Military personnel stationed in Illinois qualify as residents for the 90-day requirement regardless of their official home of record.
A petition may be filed before the 90-day residency period is complete, but the court will not enter a final judgment of dissolution until the requirement is met. Illinois has one of the shortest residency requirements among U.S. states; by comparison, California requires 6 months, New York requires 1 year for certain grounds, and Texas requires 6 months. The 90-day requirement applies to the state, not a specific county, so a spouse who moves from Cook County to DuPage County mid-case does not restart the clock.
How Can You Modify or Terminate Maintenance in Illinois?
Either party may petition to modify or terminate maintenance based on a substantial change in circumstances under 750 ILCS 5/510. Common grounds for modification include a significant increase or decrease in either party's income, the recipient's cohabitation with a new partner, retirement of the payor, or a material change in either party's health or employment status.
Maintenance automatically terminates upon the death of either party or the remarriage of the recipient. Cohabitation on a continuing, conjugal basis also constitutes grounds for termination under 750 ILCS 5/510(c), though the payor bears the burden of proving the cohabitation meets the statutory standard. Courts examine shared finances, duration of the living arrangement, and the nature of the relationship when evaluating cohabitation claims. Fixed-term maintenance cannot be extended after expiration, while reviewable maintenance allows the court to reassess at the designated review date. A voluntary reduction in income (such as quitting a job to avoid maintenance) does not automatically justify a modification; courts apply an imputed income analysis to determine whether the income reduction was made in good faith.
Frequently Asked Questions
How is alimony calculated in Illinois in 2026?
Illinois calculates maintenance using a formula under 750 ILCS 5/504(b-1): 33.33% of the payor's net income minus 25% of the payee's net income. The amount is capped so the recipient receives no more than 40% of combined net income. This formula applies when combined gross income is under $500,000.
How long does alimony last in Illinois?
Maintenance duration in Illinois is determined by multiplying the length of the marriage by a statutory factor: 0.20 for marriages of 0 to 5 years, 0.40 for 5 to 10 years, 0.60 for 10 to 15 years, 0.80 for 15 to 20 years, and 1.00 or indefinite for marriages of 20 or more years under 750 ILCS 5/504(b-1).
Is alimony taxable in Illinois?
Spousal maintenance payments in Illinois are not tax-deductible for the payor and not taxable income for the recipient for any divorce finalized after December 31, 2018. This rule applies under the federal Tax Cuts and Jobs Act of 2017 and does not expire. Illinois switched its formula from gross to net income in 2019 to reflect this change.
What is the income limit for the Illinois alimony formula?
The Illinois maintenance formula applies only when the parties' combined gross annual income is below $500,000. Above this threshold, the court has full discretion to determine both the amount and duration of maintenance based on the 14 statutory factors in 750 ILCS 5/504(a) without being bound by the formula.
Can I get alimony if my spouse and I agree to waive it?
Yes, spouses may agree to waive maintenance in a marital settlement agreement, and Illinois courts generally honor such agreements under 750 ILCS 5/502. However, a waiver in a prenuptial agreement may be challenged if the court finds it was unconscionable at the time of enforcement. Once maintenance is waived in a final divorce judgment, the waiving party cannot later petition for maintenance.
How much does it cost to file for divorce in Illinois?
Filing for divorce in Illinois costs $210 to $388 depending on county, with Cook County at the highest rate of $388. The respondent's appearance fee adds $218 to $251. Fee waivers are available for qualifying low-income parties. As of March 2026. Verify with your local clerk.
Does cohabitation end alimony in Illinois?
Cohabitation on a continuing, conjugal basis is grounds for terminating maintenance under 750 ILCS 5/510(c). The payor must prove the recipient is living with another person in a marriage-like relationship. Courts examine shared finances, duration of cohabitation, and the nature of the relationship before terminating the award.
Can alimony be modified after the divorce is final?
Either party may petition to modify maintenance based on a substantial change in circumstances under 750 ILCS 5/510. Common modification grounds include significant income changes, health changes, or retirement. Fixed-term maintenance cannot be extended after it expires, but reviewable maintenance allows court reassessment at the designated review date.
What happens to alimony if the payor goes to jail in Illinois?
Under Public Act 103-0967 (effective January 1, 2025), maintenance payments continue to accrue as arrears during incarceration. The incarcerated payor must petition the court for modification rather than relying on automatic suspension. Unpaid maintenance becomes collectible arrears upon the payor's release from incarceration.
How does the alimony calculator work for high-income couples in Illinois?
For couples with combined gross income exceeding $500,000, the standard alimony calculator formula does not apply. The court exercises full discretion, weighing the 14 factors in 750 ILCS 5/504(a) including marital standard of living, each party's earning capacity, and marriage duration. Awards in high-income cases often significantly exceed guideline amounts.