Child support · Illinois · Income shares (750 ILCS 5/505)
Illinois child support calculator 2026
Under the Illinois guidelines (income shares (750 ILCS 5/505)), a parent with gross income of $5,000 a month paying support for one child to a parent earning $3,500 would pay about $753 a month, or $9,033 a year, before the court considers any deviation. For two children it is about $1,128 a month. Parenting time changes the amount in Illinois, so the calculator asks how many overnights the children spend with each parent.
Rules checked against the Illinois statute and guidelines (effective 20 March 2026) on .
One child, headline example
$753
a month
Two children
$1,128
a month
Model
Income shares (750 ILCS 5/505)
parenting time counts
A year, one child
$9,033
headline example
Illinois child support by the paying parent's income
Guideline monthly support when the receiving parent earns $3,500 a month gross, with no health insurance or childcare add-ons and the children living mainly with the receiving parent. Net income is estimated from gross using the state's method.
| Payer's gross monthly income | 1 child | 2 children | 3 children |
|---|---|---|---|
| $2,500 | $456 | $688 | $824 |
| $3,000 | $522 | $787 | $941 |
| $4,000 | $638 | $952 | $1,128 |
| $5,000 | $753 | $1,128 | $1,341 |
| $6,000 | $843 | $1,252 | $1,476 |
| $7,500 | $1,000 | $1,476 | $1,728 |
| $10,000 | $1,212 | $1,796 | $2,111 |
| $15,000 | $1,608 | $2,353 | $2,729 |
How parenting time changes Illinois child support
Same incomes as the headline example ($5,000 and $3,500 a month, one child), with different overnights per year for the paying parent.
| Overnights a year with the paying parent | Monthly support |
|---|---|
| 0 | $753 |
| 52 | $753 |
| 104 | $753 |
| 146 | $350 |
| 182 (about half) | $158 |
Worked example, step by step
Illinois income shares (750 ILCS 5/505, HFS 2026 schedule).
| Step | Figure |
|---|---|
| Paying parent gross monthly income | $5,000.00 |
| Paying parent standardized net income (HFS 2026 table, non-majority parenting time column) | $3,921.00 |
| Paying parent net income used | $3,921.00 |
| Receiving parent gross monthly income | $3,500.00 |
| Receiving parent standardized net income (majority parenting time column) | $2,845.00 |
| Combined net income | $6,766.00 |
| Paying parent share of combined net income | 58.0% |
| Basic child support obligation, 1 child (schedule row) | $1,299.00 |
| Paying parent share of basic obligation | $752.79 |
| Guideline child support per month | $752.79 |
What the guideline assumes
Public Act 104-0733 (SB 3524), reported as signed on 31 July 2026 and effective 1 January 2027, lowers the shared care threshold to 110 overnights with a sliding adjustment between 110 and 145 overnights. The 146-overnight rule applies to orders made before then; ilga.gov could not be reached to confirm the Act text.
Also worth knowing
Net income uses the HFS standardized tax table (single filer, standard deduction; the parent with most parenting time claims the children). Courts can use an individualized tax amount instead, and can deviate from the guideline with written findings. The HFS worksheet and the court decide the order. Schedule and table effective 20 March 2026.
Get the official figure
Illinois publishes its own calculator, Illinois HFS Child Support Estimator, which follows the same guidelines with every input the court uses. Use it, and a family law attorney or the state child support agency, before relying on any number here.
Courts can deviate
The guideline amount is a presumption, not a fixed rule. A judge can order more or less where the guideline would be unjust or inappropriate, for example for high incomes, special needs, or an agreement between the parents that the court approves.
Guides and definitions
- Long term capital gains tax: 2026 rates, brackets and examples (Guide)
- Child tax credit 2026: amount, income limits and who qualifies (Guide)
- Earned income tax credit: who qualifies and how much you get (Guide)
- Child Tax Credit (The Child Tax Credit cuts US federal tax by up to $2,200 per qualifying child under 17, with up to $1,700 refundable.)
- FICA (FICA is the US payroll tax for Social Security (6.2% up to $184,500 in 2026) and Medicare (1.45%, plus 0.9% over $200,000).)
- Marginal tax rate (Your marginal tax rate is the share of your next pound or dollar of income that goes in tax and deductions.)
- Standard deduction (The standard deduction is the fixed amount US taxpayers subtract from income before federal tax: $16,100 single, $32,200 joint for 2026.)
- State Disability Insurance (SDI) (State Disability Insurance is a payroll deduction that funds short-term disability and paid family leave; California takes 1.3% of all wages in 2026.)
Child support in other states
- California (Statewide uniform guideline formula (income and time-share))
- Florida (Income shares (both parents’ net incomes combined))
- Indiana (Income shares, weekly (Indiana Child Support Guidelines))
- Texas (Percentage of the paying parent’s net resources)
All states compared · Enter your own incomes, children and parenting time
Common questions
How is child support calculated in Illinois?
Illinois uses the Income shares (750 ILCS 5/505) model. Illinois income shares (750 ILCS 5/505, HFS 2026 schedule). The court starts from the guideline amount and can adjust it.
How much is child support for one child in Illinois?
It depends on income. With the paying parent on $5,000 a month and the other parent on $3,500, the guideline amount is about $753 a month. On $4,000 it is about $638, and on $10,000 about $1,212.
How much is child support for two children in Illinois?
About $1,128 a month in the headline example, compared with $753 for one child. The guideline does not simply double for two children.
Does 50/50 custody mean no child support in Illinois?
Not necessarily. Equal time reduces the amount, and if both parents earn the same it can fall to near zero, but where incomes differ the higher earner usually still pays something under the Illinois formula.
Is this the amount a Illinois court will order?
No. It is a guideline estimate from the published rules, with net income estimated from gross. The actual order depends on the full worksheet, the evidence of each parent's income and any deviation the judge allows. Use Illinois's official calculator and get legal advice.
Sources and assumptions
- Gross monthly incomes as entered; net income for the formula is estimated with the state's standard method (single filer, standard deduction).
- No health insurance, childcare or other add-ons, and no support paid for other children, unless shown.
- 750 ILCS 5/505 (Illinois General Assembly)
- HFS 2026 Income Shares Schedule of Basic Obligations (PDF)
- HFS 2026 Gross to Net Income Conversion Table (PDF)
- HFS 2026 Addendum to the Schedule and Net Income Table (PDF)
- HFS Income Shares guidelines page
- Illinois HFS Child Support Estimator
A guideline estimate, not legal advice. The court decides child support.