Illinois grants roughly 30,000 divorces per year under a pure no-fault system. Whether you're just starting to consider divorce or already in the process, this guide covers the law, the timeline, how child support and maintenance are calculated, and how property gets divided — with interactive calculators built on Illinois statutes.
Under 750 ILCS 5/401, the only ground for divorce in Illinois is irreconcilable differences. You do not need to prove adultery, abuse, or any fault. Neither spouse can block a divorce by refusing to agree — if one spouse wants a divorce, they will get one.
6-Month Rule: If both spouses agree, there is no waiting period. If one spouse contests, a continuous 6-month separation creates an irrebuttable presumption of irreconcilable differences — meaning the court must grant the divorce.
From filing to final judgment, here's exactly what happens in an Illinois divorce.
At least one spouse must have lived in Illinois for 90 days before filing. You file in the county where either spouse resides.
File a Petition for Dissolution of Marriage at your county circuit court clerk's office. You'll also file a Summons, Financial Affidavit, and any parenting plan documents if children are involved.
Your spouse must be formally served with the divorce papers. They then have 30 days to respond. If they can't be located, service by publication is available.
Both spouses must complete a Financial Affidavit disclosing all income, assets, debts, and expenses. This is mandatory and must be filed with the court.
Most Illinois divorces settle through negotiation or mediation. If you can't agree on property, support, or custody, the case goes to trial and a judge decides.
Once all issues are resolved, the judge signs a Judgment for Dissolution of Marriage. This is the final legal document ending the marriage.
Illinois uses the Income Shares model (750 ILCS 5/505) — both parents' incomes are combined to determine a basic support obligation, then each parent pays their proportional share. Enter annual net income (after taxes, FICA, and mandatory deductions).
Based on the Illinois Income Shares model (750 ILCS 5/505). Enter annual net income (after taxes).
365 total — enter Parent 1's share
Since 2019, Illinois uses a statutory formula for maintenance when combined gross income is $500,000 or less (750 ILCS 5/504). Duration is based on the length of the marriage. Enter annual gross income (before taxes).
Based on the Illinois statutory formula (750 ILCS 5/504). Applies when combined gross income ≤ $500,000.
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Illinois follows equitable distribution — marital property is divided fairly, not necessarily 50/50. Under 750 ILCS 5/503, courts consider each spouse's contributions, economic circumstances, and the duration of the marriage.
Examples: Family home, retirement accounts earned during marriage, joint bank accounts, vehicles purchased during marriage
Illinois courts consider contributions of each spouse, duration of marriage, economic circumstances, and other factors under 750 ILCS 5/503.
Examples: Property owned before marriage, inheritances, gifts from third parties, personal injury settlements
Must be kept separate — commingling non-marital funds with marital funds can convert them to marital property.
Examples: 401(k), pension, IRA contributions made during the marriage
Requires a Qualified Domestic Relations Order (QDRO) to divide without tax penalty.
Examples: Business started or grown during marriage
Valuation is often contested — forensic accountants and business appraisers are commonly used.
Examples: Mortgage, car loans, credit card debt incurred during marriage
Creditors are not bound by divorce decrees — both spouses remain liable to lenders regardless of who the court assigns the debt to.
Common questions about Illinois divorce law, answered with specific statute citations.
Legal Disclaimer: The calculators and information on this page are for educational purposes only and do not constitute legal advice. Child support and maintenance calculations are estimates — actual court orders depend on verified net income, special circumstances, and judicial discretion. Always consult a licensed Illinois family law attorney for advice specific to your situation. Statutes verified against ilga.gov. Last reviewed: June 2026.
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