Illinois Spousal Support Calculator
Calculate Maintenance Under 750 ILCS 5/504 — Updated for the 2025 33.33% / 25% Statutory Formula
📋 2025 Illinois Statutory Formula (P.A. 103-1234)
Monthly Maintenance = (33.33% × Payor Net Income) − (25% × Recipient Net Income)
Subject to: Award + Recipient Income ≤ 40% of Combined Net Income
For combined gross annual income above $500,000 the formula is a guideline only — court exercises full discretion. Calculator uses gross income as input; actual orders are based on net income.
Use this free Illinois spousal maintenance calculator to estimate how much support you may pay or receive under 750 ILCS 5/504. Whether your divorce is in Chicago (Cook County), DuPage County, Lake County, or anywhere else in Illinois, this tool applies the updated 2025 33.33%/25% formula — including the 40% combined income cap and the $500,000 high-income threshold. Wondering how long maintenance lasts in Illinois, or which type applies to your case? Enter your details below for a step-by-step estimate. Always consult a licensed Illinois divorce attorney or Illinois family law lawyer for advice specific to your case.
Income Information
Marriage Details
Marriage less than 5 years? (auto-set from duration)
Marriage 20+ years? ℹ️Marriages of 20+ years may qualify for permanent/indefinite maintenance at the court's discretion. Even in long marriages, courts may award fixed-term or reviewable maintenance if the recipient is not diligently pursuing self-sufficiency. See In re Marriage of Chapa (2024).
Is recipient custodial parent? ℹ️Check if the maintenance recipient has primary physical custody of minor children. This is a relevant factor under 750 ILCS 5/504(a).
Illinois-Specific Factors
Domestic violence involved? ℹ️Under 750 ILCS 5/504(a), domestic violence is an explicit statutory factor. Courts may increase maintenance for victims and consider the impact on the recipient's earning capacity and needs.
Illinois Domestic Violence Factor:
- Explicitly listed under 750 ILCS 5/504(a)
- May increase maintenance amount for the victim
- Court considers impact on recipient's long-term earning capacity and safety
See: 750 ILCS 5/504(a)(14)
Fault-based divorce? ℹ️Illinois is primarily a no-fault state, but marital misconduct (e.g., financial dissipation of assets) may be considered as a factor under 750 ILCS 5/504(a). This calculator does not apply a direct adjustment for fault.
Illinois Fault Considerations:
- Illinois is primarily a no-fault divorce state
- Marital misconduct is generally not a direct maintenance factor
- Financial dissipation of assets may be considered by the court
See: 750 ILCS 5/504(a)
Needs & Resources
Earning Capacity & Recipient Profile
Recipient sacrificed career for marriage? ℹ️Explicit factor under 750 ILCS 5/504(a)(9). If the recipient left a career or education opportunity to support the marriage or raise children, the court may increase maintenance to compensate for lost earning potential.
Recipient has a disability? ℹ️Physical or mental disability limiting the recipient's ability to work is a significant factor under 750 ILCS 5/504(a)(8). May justify increased amount and/or longer duration.
Duration Factors
Maintain marital standard of living? ℹ️Illinois courts consider the standard of living established during the marriage under 750 ILCS 5/504(a)(7). More relevant in long-term marriages and may support higher or longer maintenance awards.
Recipient has significant separate property? ℹ️If the recipient holds significant non-marital property, their financial need may be reduced, which is a factor under 750 ILCS 5/504(a)(2).
Disclaimer: This calculator provides estimates only and is not legal advice. Updated for the 2025 33.33%/25% formula amendment (P.A. 103-1234). Consult a licensed Illinois family law attorney for advice specific to your case.
2025 Statutory Update: The Illinois Marriage and Dissolution of Marriage Act was amended by P.A. 103-1234 (2025) — changing the formula from 30%/20% to 33.33%/25%. Maintenance during payor incarceration is no longer automatically suspended; a modification petition is required.
Illinois Spousal Maintenance Calculation Results
Maintenance Type Determination
Recommended Maintenance Type:
Primary Factors:
Monthly Maintenance Amount
Guideline Amount:
Statutory Basis:
Duration of Maintenance
Recommended Duration:
Illinois Guideline:
Judicial Considerations
Likely Judicial Range:
Key Factors:
Illinois Maintenance Case Law Examples
In re Marriage of Thompson (2025)
2025 IL App (1st) 240562 (Ill. App. Ct. 2025)
The appellate court upheld the new 33.33%/25% statutory formula, clarifying that the 40% cap on combined net income remains mandatory. The court rejected a constitutional challenge to the 2025 amendment, affirming the legislature's authority to update the formula percentages.
In re Marriage of Chapa (2024)
2024 IL App (2d) 230266 (Ill. App. Ct. 2024)
For marriages of 20+ years, permanent maintenance is not automatic. The recipient must demonstrate diligent efforts toward self-sufficiency. A lack of effort can justify reviewable or fixed-term maintenance even in long marriages.
In re Marriage of Heroy (2017)
2017 IL 120205 (Ill. Sup. Ct. 2017)
Cohabitation alone does not automatically terminate maintenance in Illinois. The payor must file a petition proving a substantial change in the recipient's financial circumstances to obtain a modification.
In re Marriage of O'Brien (2011)
2011 IL 109039 (Ill. Sup. Ct. 2011)
Professional degrees are not marital property, but the earning potential they generate may be considered by the court when setting maintenance amounts and duration under 750 ILCS 5/504.
Modifying Maintenance in Illinois
Under 750 ILCS 5/510(a-5), maintenance can be modified upon a showing of a substantial change in circumstances.
1. Legal Standards for Modification
Substantial Change Required: The change must be material and ongoing — temporary fluctuations are insufficient (750 ILCS 5/510(a-5)).
Automatic Termination on Remarriage: Maintenance automatically terminates upon the recipient's remarriage (750 ILCS 5/510(c)).
Cohabitation Is Not Automatic: Cohabitation alone does NOT terminate maintenance — the payor must file a petition and prove a substantial change in the recipient's financial circumstances (In re Marriage of Heroy, 2017 IL 120205).
Incarceration — No Automatic Suspension (2025): As of the 2025 IMDMA amendments (P.A. 103-1234), maintenance is no longer automatically paused during payor incarceration — a formal modification petition must be filed (750 ILCS 5/510).
20+ Year Marriages — Permanent Not Guaranteed: Even in long marriages, the recipient must show diligent efforts toward self-sufficiency; failure to do so can result in reviewable or fixed-term maintenance rather than permanent (In re Marriage of Chapa, 2024).
2. Common Grounds for Modification
Significant Income Change: Job loss, pay reduction, or major income increase for either party.
Recipient's Remarriage: Maintenance terminates automatically by operation of law; payor should still file to formally close out the order.
Proven Cohabitation: A change in the recipient's financial circumstances arising from a cohabiting relationship, proven by petition (Heroy).
Payor's Retirement (65+): Retirement at a reasonable age may constitute a substantial change; court weighs health, retirement assets, and recipient's ongoing needs.
Recipient's Improved Earning Capacity or Failure to Pursue Self-Sufficiency: May justify reduction or termination, especially after reviewable-term expires (In re Marriage of Chapa, 2024).
Payor's Incarceration: No automatic suspension — must petition; support may continue to accrue as debt during imprisonment.
3. Step-by-Step Modification Process
Step 1 – Gather Evidence: Tax returns (2–3 years), pay stubs, retirement account statements, medical records, or proof of cohabitation and financial interdependence.
Step 2 – File a Petition for Modification: Submit to the circuit court that entered the original order, with updated financial affidavits.
Step 3 – Serve Notice: Formally serve the other party per Illinois Supreme Court Rules; proof of service required.
Step 4 – Mediation: Many Illinois counties (Cook, DuPage, Lake) require or encourage mediation before a contested hearing.
Step 5 – Court Hearing: If unresolved, present evidence before the circuit court judge.
Step 6 – Order on Modification: Modifications are not retroactive — effective from the date the petition is filed.
4. Critical Practical Considerations
Never stop paying without a court order: Arrears accumulate and the payor risks contempt proceedings.
No retroactive modification: Act promptly when circumstances change — relief runs only from the filing date.
Professional degrees are not marital property: But the earning potential they generate may influence maintenance amounts and duration (In re Marriage of O'Brien, 2011 IL 109039).
2025 formula now applies (33.33%/25%): Confirm whether an existing order was set under the old 30%/20% formula — the new percentages apply to modification orders entered after the effective date of P.A. 103-1234.
750 ILCS 5/504, 5/510(a-5), 5/510(c) | P.A. 103-1234 (2025) | In re Marriage of O'Brien, 2011 IL 109039 | In re Marriage of Heroy, 2017 IL 120205 | In re Marriage of Chapa, 2024 IL App (2d) 230266