Illinois Alimony Calculator
Estimate spousal maintenance under Illinois' statutory formula (750 ILCS 5/504, as of Jan. 1, 2019). Enter net monthly incomes and years married. Free, instant, no data stored.
Estimated Maintenance
Presumptive statutory amount using net income. Not to exceed 40% of combined net income. Courts may deviate for cause.
Source: 750 ILCS 5/504(b-1) (as of Jan. 1, 2019).
How the Illinois formula works
Illinois courts calculate maintenance (alimony) using a two-part statutory formula under 750 ILCS 5/504(b-1):
- Amount: 33.33% of the paying spouse's net income minus 25% of the receiving spouse's net income. The result cannot exceed 40% of the spouses' combined net income, and cannot be negative.
- Duration: The number of years of the marriage multiplied by a factor from the statutory table — ranging from 0.20 for short marriages to 0.80 for 19-year marriages. For marriages of 20 or more years, the court may order maintenance for an indefinite duration.
Net income under the formula is calculated the same way as in Illinois child support proceedings: gross income minus federal and state income taxes, Social Security and Medicare taxes, mandatory pension contributions, and union dues.
Courts may deviate from the guideline amounts for cause, including the standard of living during the marriage, each spouse's property, and the time needed for the recipient to become self-supporting.
Frequently asked questions
Does Illinois always award maintenance? No. The court first determines whether maintenance is appropriate at all. The formula applies only after that threshold is met.
Can both spouses earn maintenance? The formula produces a single number; if the result is zero or negative, no maintenance is payable. In practice, only one spouse receives maintenance.