Illinois Alimony Calculator
Estimate spousal support and how long it lasts under 750 ILCS 5/504(b-1). Enter your numbers below for an instant estimate with a step-by-step breakdown and statute citations.
Illinois Alimony Calculator
This state publishes a guideline equation that takes a share of the payor’s income and subtracts a share of the payee’s.
Based on 750 ILCS 5/504(b-1) · Verified June 1, 2026
Enter income details to see your estimate
Factors Illinois Courts Weigh
- •Each spouse's income, property, and needs
- •The realistic present and future earning capacity of each spouse
- •Impairment of earning capacity from devoting time to domestic duties
- •Time needed for the recipient to acquire education or training
- •The standard of living established during the marriage
- •The duration of the marriage
- •Contributions by the recipient to the other spouse's career
- •Any valid agreement between the parties
How Illinois Alimony Works
- •Illinois calls alimony "maintenance." The statutory guideline applies only when the parties' combined gross annual income is below $500,000 and the payor has no prior child-support or maintenance obligation.
- •The amount equals 33⅓% of the payor's net income minus 25% of the payee's net income — but the payee's income plus maintenance cannot exceed 40% of the parties' combined net income.
- •The duration is set by a fixed schedule tied to the length of the marriage, so two couples with the same incomes but different marriage lengths get very different terms.
- •Above the $500,000 income threshold, the court is not bound by the formula and sets maintenance using the statutory factors instead.
This is an estimate for educational purposes only, not legal advice. Alimony is highly discretionary; a Illinois judge can order a different amount or duration. Consult a licensed Illinois family-law attorney about your situation.
How Illinois Calculates Alimony
Illinois addresses spousal support under 750 ILCS 5/504(b-1). It uses a guideline equation that takes a percentage of the payor's net income and subtracts a percentage of the payee's net income, with statutory caps. The calculator above applies that equation to your figures and shows each step.
Unlike child support, alimony is one of the most discretionary areas of family law. Even in states with a guideline equation, the figure is a starting point a judge can adjust after weighing the statutory factors, the length of the marriage, and each spouse's needs and ability to pay. Treat any number here as an informed estimate, not a guaranteed award.
Key Rules in Illinois
- Illinois calls alimony "maintenance." The statutory guideline applies only when the parties' combined gross annual income is below $500,000 and the payor has no prior child-support or maintenance obligation.
- The amount equals 33⅓% of the payor's net income minus 25% of the payee's net income — but the payee's income plus maintenance cannot exceed 40% of the parties' combined net income.
- The duration is set by a fixed schedule tied to the length of the marriage, so two couples with the same incomes but different marriage lengths get very different terms.
- Above the $500,000 income threshold, the court is not bound by the formula and sets maintenance using the statutory factors instead.
How Long Alimony Lasts in Illinois
Illinois sets the term by multiplying the length of the marriage by a statutory factor that increases with the length of the marriage. After 20 years the court may order maintenance for the length of the marriage or indefinitely.
What Counts as Income
Illinois's formula runs on each spouse’s net income — gross pay minus taxes and mandatory deductions. Courts can also impute income to a spouse who is voluntarily unemployed or underemployed, meaning support can be based on what a spouse could earn rather than what they currently do. Use your most recent pay stubs and tax return for the most accurate estimate.
Eligibility & Modifying an Order
Not every divorce results in alimony. Illinois courts award it when one spouse has a genuine financial need and the other has the ability to pay, judged against the factors above.
Alimony orders can usually be modified when there is a substantial change in circumstances — for example, a significant change in either spouse's income, the recipient's remarriage or cohabitation, retirement, or the payor's loss of employment. The specific rules and any non-modifiable agreements depend on your court order and Illinois law.
Frequently Asked Questions
Is this Illinois alimony calculator accurate?
It applies the Illinois guideline from 750 ILCS 5/504(b-1) to the numbers you enter, so it gives a close estimate of a typical guideline award. It is not an official court calculation — a judge can order a different amount after weighing the statutory factors.
Is alimony taxable in Illinois?
For divorces finalized after December 31, 2018, alimony is not deductible by the payor and is not taxable income to the recipient under federal law. Most states follow the federal treatment, but check Illinois's current rules for state income tax.
Does cheating affect alimony in Illinois?
It depends on the state. Some states let courts consider marital misconduct among the alimony factors, while others bar it entirely. Review 750 ILCS 5/504(b-1) and speak with a Illinois attorney about how fault is treated where you live.
Can alimony be changed later?
Usually yes. Alimony can often be modified when there is a substantial change in circumstances — such as a large change in income, the recipient's remarriage or cohabitation, or the payor's retirement — unless your order or agreement makes it non-modifiable.
Disclaimer
This calculator provides estimates for educational purposes only and is not legal advice. Alimony is highly fact-specific and discretionary; the amount and duration a Illinois court actually orders may differ significantly from any estimate here. For advice about your situation, consult a licensed Illinois family-law attorney.
Know someone who could use this? Share this free tool: