Illinois Alimony Calculator
Estimate spousal support (maintenance) amount and duration in Illinois. Updated for 2026.
Last reviewed July 2026 · Free · Nothing you enter is stored
Statutory formula state
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estimated monthly spousal support ·
Educational estimate, not legal advice. Courts apply the statutory formula but can deviate.
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How alimony works in Illinois
Illinois has a statutory guideline formula: 33% of the paying spouse's net income minus 25% of the receiving spouse's net income, capped so the recipient's total income doesn't exceed 40% of the couple's combined income.
Governing law: 750 ILCS 5/504 — The clearest statutory guideline in the country: 33⅓% of the payor's net income minus 25% of the recipient's, capped so the recipient's total doesn't exceed 40% of combined net income. Applies when combined gross income is under $500,000/yr; courts may deviate with written findings.
Frequently asked questions
How is alimony calculated in Illinois?
Illinois has a statutory guideline formula: 33% of the paying spouse's net income minus 25% of the receiving spouse's net income, capped so the recipient's total income doesn't exceed 40% of the couple's combined income. See 750 ILCS 5/504.
How long does alimony last in Illinois?
Duration equals the length of the marriage times a statutory multiplier that rises from 0.20 (under 5 years) in 4-point steps to 0.80 (19 years); at 20+ years the court awards a term equal to the marriage length or indefinite maintenance (750 ILCS 5/504(b-1)).
What types of alimony does Illinois recognize?
Illinois recognizes: temporary, fixed-term, reviewable, indefinite, reserved. The clearest statutory guideline in the country: 33⅓% of the payor's net income minus 25% of the recipient's, capped so the recipient's total doesn't exceed 40% of combined net income. Applies when combined gross income is under $500,000/yr; courts may deviate with written findings.
Is alimony taxable in Illinois?
For divorces finalized after 2018, federal law (TCJA) makes alimony non-deductible for the payer and non-taxable for the recipient. A few states differ for state income tax — confirm with a tax professional.
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