Rex says
Illinois's number on paper is one formula — what a judge actually signs off on depends a lot on facts this calculator can't see.
Try a scenario
Click to load — tweak from there.Inputs
Result
Estimated guideline monthly support
$1,000
Payor's net income used
$7,000
Payee's net income used
$3,000
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How to use this
- 1Enter paying spouse's monthly net income ($).
- 2Enter receiving spouse's monthly net income ($).
- 3Enter child support already paid by payor ($/mo).
- 4Read your estimated guideline monthly support on the right — it updates as you type.
- 5Hit Share to keep the scenario or send it to someone.
About this calculator
Estimates spousal support in Illinois using that state's statutory formula (33% payor net minus 25% payee net, capped at 40% combined). Enter each spouse's monthly net income; the tool applies the percentage formula associated with Illinois's guideline and shows the resulting monthly amount. This is an estimate only, not legal advice — actual awards depend on the specific court, county guideline worksheets, and judicial discretion, and a judge may deviate from the guideline for good cause.
Worked example
Using the values the calculator loads with:
Inputs
- Paying spouse's monthly net income: 7000 $
- Receiving spouse's monthly net income: 3000 $
- Child support already paid by payor: 0 $/mo
Results
- Estimated guideline monthly support: $1,000
- Payor's net income used: $7,000
- Payee's net income used: $3,000
What each field means
Inputs
- Paying spouse's monthly net income ($)
- The paying spouse's monthly net income used in the calculation, measured in $. Starts at 7000 $ so you have a working example on load.
- Receiving spouse's monthly net income ($)
- The receiving spouse's monthly net income used in the calculation, measured in $. Starts at 3000 $ so you have a working example on load.
- Child support already paid by payor ($/mo)
- The child support already paid by payor used in the calculation, measured in $/mo. Starts at 0 $/mo so you have a working example on load.
Results
- Estimated guideline monthly support
- Returned as a money amount in US dollars and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Payor's net income used
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Payee's net income used
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
What is the Illinois formula for alimony/spousal support?
statutory formula (33% payor net minus 25% payee net, capped at 40% combined).
What is Illinois's maintenance formula cap?
Illinois calculates maintenance as 33.3% of the payor's net income minus 25% of the payee's net income, but the result cannot push the recipient's total income (support plus their own net income) above 40% of the couple's combined net income.
Is Illinois spousal support guaranteed at this amount?
This is an estimate only, not legal advice — actual awards depend on the specific court, county guideline worksheets, and judicial discretion, and a judge may deviate from the guideline for good cause.
Does this account for taxes on alimony?
No — since 2019, alimony is not federally tax-deductible for the payor or taxable income for the recipient for divorces finalized after 2018; this estimate is a pre-tax guideline figure only.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Illinois Alimony Calculator (Illinois Support Guideline). Retrieved from https://www.revenuelab.fyi/toolbox/alimony-calculator-illinois
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/alimony-calculator-illinois" target="_blank" rel="noopener">Illinois Alimony Calculator (Illinois Support Guideline) — RevenueLab</a> (2026).</p>
Source: [Illinois Alimony Calculator (Illinois Support Guideline) — RevenueLab](https://www.revenuelab.fyi/toolbox/alimony-calculator-illinois) (2026).