Illinois Alimony / Spousal Support Estimator

Illinois uses a statutory formula under 750 ILCS 5/504: maintenance equals 33.33% of the payor's net income minus 25% of the recipient's net income. The recipient's total income including maintenance cannot exceed 40% of combined net income. This guideline formula applies when both spouses' combined gross annual income is below $500,000 and the payor has no prior maintenance or child support obligations.

Illinois courts award four types of maintenance under 750 ILCS 5/504: fixed-term maintenance with a specific end date, indefinite maintenance with no termination date, reviewable maintenance subject to court review at a set time, and reserved maintenance where the court preserves the right to award support later. Temporary maintenance may also be ordered during the divorce proceedings under Section 501.

Illinois ties maintenance duration to marriage length under 750 ILCS 5/504(b-1)(1)(B). Marriages of 5 years or less receive 20% of the marriage length; 5–10 years receive 40%; 10–15 years receive 60%; 15–20 years receive 80%. Marriages lasting 20 years or more may receive maintenance for the full marriage length or indefinitely at the court's discretion.

Under 750 ILCS 5/504(a), Illinois courts consider each spouse's income and property, realistic present and future earning capacity, any impairment from devoting time to domestic duties, time needed to acquire education or job training, the standard of living during the marriage, marriage duration, and each party's age and health. Courts may deviate from the guideline formula based on these factors.

Illinois allows maintenance modification upon a substantial change in circumstances under 750 ILCS 5/510. Maintenance terminates automatically upon the recipient's remarriage or either party's death. Cohabitation on a 'resident, continuing conjugal basis' also warrants termination, though the payor must petition the court and prove the cohabitation. Fixed-term maintenance cannot be extended beyond its original end date.

Adultery does not affect maintenance awards in Illinois. Section 504 of the IMDMA explicitly states that maintenance is awarded 'without regard to marital misconduct.' Illinois operates as a purely no-fault divorce state. However, an affair may indirectly impact property division if the unfaithful spouse committed dissipation — wasteful spending of marital assets on the extramarital relationship.

Spousal maintenance is not taxable for the recipient and not tax-deductible for the payor under federal law for divorce agreements executed after December 31, 2018. The Tax Cuts and Jobs Act of 2017 eliminated the federal tax deduction for maintenance payments. Illinois conforms to federal tax treatment, so neither party reports maintenance as income or a deduction on state returns.

Illinois is one of the few states that allows spouses to waive maintenance rights in a prenuptial agreement under the Illinois Uniform Premarital Agreement Act (750 ILCS 10). However, the waiver cannot be unconscionable or cause undue hardship to the spouse giving up support. If unforeseen circumstances make the waiver unreasonable at the time of divorce, the court may decline to enforce it.