Illinois Spousal Maintenance Calculator
Apply the 33⅓% – 25% formula, 40% income cap, and statutory duration multipliers in minutes.
Run the Guideline Test
Enter monthly income, allowable deductions, and marriage length. We test guideline applicability, compute the monthly amount, and project the statutory duration range.
Which best describes you?
Illinois Spousal Maintenance
750 ILCS 5/504 guideline evaluation
Need more information
Enter monthly gross income for both parents to estimate maintenance.
Understanding Illinois Maintenance
The Illinois Marriage and Dissolution of Marriage Act relies on net income figures to determine maintenance. Courts must first see whether guidelines apply, apply the 33⅓% – 25% formula, enforce the 40% cap, and then review statutory factors to decide on deviations.
Key Safeguards
- $500k combined gross income ceiling for guidelines.
- 40% cap ensures payee income does not exceed 40% of combined net.
- Duration factors escalate as the marriage length increases.
Best Practices
- Pair maintenance output with the child support estimate for accurate sequencing.
- Model both guideline and non-guideline scenarios when assets or income exceed thresholds.
- Document statutory deviation factors (750 ILCS 5/504(a)) when negotiating adjustments.
Guideline Workflow
- Verify applicability. Check combined gross income and existing obligations to ensure guidelines apply.
- Calculate the formula. Apply 33⅓% of the payor’s net minus 25% of the payee’s net. If negative, maintenance is $0.
- Apply the 40% cap. Reduce the award if the payee would exceed 40% of combined net income.
- Determine duration. Multiply the marriage length by the statutory factor to show the advisory duration window.
- Integrate child support. Adjust each parent’s net income with the maintenance transfer before modeling Income Shares child support.
Guideline Health Check
Quickly confirm whether the case is guideline-eligible or requires discretionary analysis.
Duration Forecast
Display minimum and maximum months to anchor settlement negotiations.
Deviation Notes
Flag scenarios where guideline maintenance is $0 or non-applicable so you can prepare statutory arguments.
Frequently Asked Questions
When do Illinois maintenance guidelines apply?
Guidelines apply when combined gross annual income is under $500,000 and the payor has no existing support obligations to someone else. Otherwise, maintenance is discretionary.
How is the maintenance amount calculated?
The guideline amount equals 33⅓% of the payor’s net income minus 25% of the payee’s net income. The result is reduced if the payee would exceed 40% of combined net income.
How is the duration determined?
Multiply the length of the marriage by the statutory factor (0.20 for under five years up to 0.80 for nineteen years). Marriages over 20 years may receive maintenance equal to the length of the marriage or indefinite.
Does maintenance affect child support?
Yes. Illinois requires maintenance to be calculated first so the transfer can adjust each parent’s net income before computing Income Shares child support.
Integrate Maintenance with Child Support
Use this maintenance output alongside the Illinois child support calculator to deliver a complete financial proposal that mirrors courtroom calculations.
Recalculate Maintenance