Illinois Alimony and Child Support Calculator
This advanced calculator helps estimate alimony (maintenance) and child support obligations according to Illinois guidelines, with customization options for various international considerations. Adjust the inputs below to calculate estimated payments based on current Illinois laws.
Input Details
Calculation Results
Monthly Child Support
Monthly Alimony (Maintenance)
Combined Monthly Payment
Payment Breakdown
How Illinois Support Calculations Work
Illinois uses specific formulas to determine both child support and alimony (maintenance). Child support is calculated based on the income shares model, which considers both parents’ incomes and the number of children. Alimony calculations consider the length of marriage, income disparity, and other factors.
Key Factors in Illinois Calculations:
International Comparison
While this calculator uses Illinois guidelines, it’s helpful to understand how different jurisdictions approach support calculations worldwide:
| Country/Region | Child Support Approach | Alimony Approach | Key Differences |
|---|---|---|---|
| Illinois, USA | Income Shares Model | Formula-based with discretion | Uses specific percentages based on combined income |
| California, USA | Percentage of Income | Discretionary based on need/ability | Fixed percentages, simpler calculation |
| United Kingdom | Formula with basic rate + additions | Needs-based with clean break principle | Considers resident vs non-resident parent |
| Canada | Federal/Provincial Guidelines | Discretionary based on circumstances | Tables determine base amount by province |
| Australia | Formula based on costs of children | Limited to special circumstances | Considers both parents’ income and care percentage |
| Germany | Düsseldorf Table (standardized) | Based on need and marriage duration | Fixed table amounts based on income brackets |
Frequently Asked Questions
This calculator provides estimates based on Illinois guidelines and formulas. Actual court-ordered amounts may vary based on specific circumstances, judge’s discretion, and additional factors not included in this calculation. Always consult with a family law attorney for legal advice.
Yes, Illinois uses a formula for temporary maintenance. For marriages under 20 years, maintenance is calculated as 33.33% of the payer’s net income minus 25% of the recipient’s net income. For marriages over 20 years, judges have more discretion. The result cannot exceed 40% of the parties’ combined net income.
Illinois uses the “income shares” model which considers both parents’ incomes. The basic formula calculates what the child would have received if the parents lived together, then allocates this amount proportionally based on each parent’s income percentage of the combined total.
This adds complexity to support calculations. Generally, the state/country where the child resides has jurisdiction. Our calculator includes an international considerations factor to help estimate how multi-jurisdictional cases might affect calculations. The Uniform Interstate Family Support Act (UIFSA) governs interstate cases in the US.
The model year option allows you to adjust calculations for different years. This is useful for planning future agreements or understanding how guideline changes might affect payments. Enter any year (2024, 2025, 2026, etc.) and the calculator will adjust guidelines accordingly based on historical patterns and projected changes.
Important Disclaimer
This Illinois alimony and child support calculator provides estimates only and is not a substitute for legal advice from a qualified attorney. Calculations are based on Illinois guidelines and may not reflect actual court orders. Laws change regularly, and individual circumstances can significantly affect outcomes. For international cases, consult legal professionals in all relevant jurisdictions. Always verify calculations with current official guidelines and legal counsel.