Updated for 2026 guidelines
Illinois Child Support Calculator 2026
Illinois publishes fresh guideline tables every year, and the 2026 set took effect in March. This page runs both parents’ gross incomes through the official conversion table, looks up the schedule, and applies the 146-overnight shared care formula when it fits.
Reviewed by SupportDecode Editorial Team Page content reviewed Sources Methodology Update log
Estimate Illinois child support
Estimated monthly child support: $612.78
The paying parent pays this amount to the receiving parent each month.
| Line item | Amount |
|---|---|
| Standardized monthly net incomes (payer plus recipient)2026 Gross to Net Income Conversion Table (standardized tax amounts) (Illinois HFS) | $10,585.00 |
| Basic support obligation (2026 Schedule of Basic Obligations)2026 Illinois Schedule of Basic Obligations (Illinois HFS) | $2,594.00 |
| Payer share of combined net income (percent)750 ILCS 5/505 (child support) and 5/504 (maintenance) (Illinois General Assembly (ilga.gov)) | $55.75 |
| Shared care obligation: basic times 1.5750 ILCS 5/505 (child support) and 5/504 (maintenance) (Illinois General Assembly (ilga.gov)) | $3,891.00 |
| Each portion multiplied by the other parent's time share, then offset (payer net owing)A negative amount means the recipient parent owes the payer.750 ILCS 5/505 (child support) and 5/504 (maintenance) (Illinois General Assembly (ilga.gov)) | $612.78 |
| Total monthly support750 ILCS 5/505 (child support) and 5/504 (maintenance) (Illinois General Assembly (ilga.gov)) | $612.78 |
Assumptions
- Standardized net income via the 2026 HFS gross-to-net conversion table unless a net income is stipulated; income shares carried unrounded and dollar amounts rounded to cents.
Continue with this income in the PayDecode take-home calculator
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Estimate only. The court or state agency calculation controls.
Illinois guidelines, effective 2026-03-20.
Illinois guideline facts
- Guideline model
- Income shares on standardized net income, since July 1, 2017source
- Statute
- 750 ILCS 5/505; tables published by HFS under 505(a)(1)source
- Current tables
- 2026 conversion table and schedule (2026 Addendum dated March 13, 2026)source
- Schedule range
- $25.00 to $27,374.99 combined monthly net, in $50 steps, 1 to 6 childrensource
- Shared care line
- 146 overnights for each parent triggers the 1.5x offset formulasource
- Minimum order
- $40 per child per month (max $120) for gross income at or below about $997.50source
- Official estimator
- HFS runs its own Child Support Estimator onlinesource
- Parameter set effective
- March 20, 2026 (2026 HFS tables)source
- Next scheduled data review
- March 20, 2027source
How the Illinois guidelines work
Illinois has used the income shares model since July 1, 2017, under 750 ILCS 5/505. The statute sets the method, and the Department of Healthcare and Family Services publishes the two tables that carry the actual numbers: a Gross to Net Income Conversion Table and a Schedule of Basic Obligations. HFS refreshes both every year; the 2026 versions were published with an addendum dated March 13, 2026.
The conversion table is the Illinois signature. Most states leave you to figure out net income on your own. Illinois prints a standardized table that turns each parent’s monthly gross into net using fixed tax assumptions, so two parents with the same paycheck get the same net. The table has two columns, one for the parent with the majority of parenting time and one for the other parent, because their assumed tax treatment differs. Parents can instead compute an individualized net from actual taxes if they prefer; the statute allows either route.
The two net incomes are added and looked up on the Schedule of Basic Obligations, which runs in $50 steps up to $27,374.99 of combined monthly net and covers 1 to 6 children. Each parent then owes a share of that basic obligation in proportion to their own net income. In an ordinary case, the parent with fewer overnights pays their share to the other parent.
Parenting time changes the formula at exactly 146 overnights a year, which is 40 percent of 365. When each parent has the children at least 146 nights, the basic obligation is multiplied by 1.5, split between the parents by income share, and then each parent’s portion is multiplied by the other parent’s share of the nights. The two results are offset, and the parent with the bigger number pays the difference. Crossing from 145 to 146 nights can move the payment a lot, which is why Illinois lawyers talk about the 146-night line so much.
Very low incomes get a floor instead of the formula. A paying parent whose gross income is at or below 75 percent of the federal poverty guideline for one person, about $997.50 a month in 2026, is presumed to owe $40 a month per child, capped at $120 total. Child care and the children’s health insurance premium ride on top of the basic figure, divided between the parents by income share.
A paying parent who already pays court-ordered support for children of another relationship gets that amount deducted from net income before the schedule lookup. Above the top of the schedule, the court sets support case by case, and the guideline amount at the highest bracket acts as the floor.
Worked example: $8,000 and $6,000 gross, 2 children, exactly 146 overnights
- Take a paying parent earning $8,000 gross a month and a receiving parent earning $6,000, with 2 children. The paying parent has the children 146 nights a year and the receiving parent has 219. Because each parent is at 146 nights or more, the shared physical care formula in 750 ILCS 5/505(a)(3.8) applies.
- First the conversion table. The paying parent does not have the majority of parenting time, so the non-majority column turns $8,000 gross into $5,901 net. The receiving parent gets the majority column, which turns $6,000 into $4,684.
- Combined net income is $5,901 plus $4,684, which is $10,585. On the 2026 schedule, the bracket from $10,575.00 to $10,624.99 gives a basic obligation of $2,594 for 2 children.
- Shared care multiplies that by 1.5, giving $3,891.00. The paying parent earns 55.7487 percent of the combined net, so their slice is $2,169.18 and the receiving parent’s slice is $1,721.82.
- Now each slice is multiplied by the other parent’s share of the nights. The paying parent’s $2,169.18 times 219/365, which is 60 percent, gives $1,301.51. The receiving parent’s $1,721.82 times 146/365, which is 40 percent, gives $688.73.
- The difference is what changes hands: $1,301.51 minus $688.73 is $612.78 a month, paid by the higher earner. Without the shared care formula, the same incomes would produce a much larger payment, which is what makes the 146th overnight matter.
The steps above follow the calculation method described on our methodology page.
Illinois guideline history
- Illinois switched from a flat percentage of the paying parent’s net income to the income shares model (P.A. 99-764).source
- The federally required four-year review of the Illinois guidelines, covering 2022, was published, feeding the annual table updates that followed.source
- HFS published the 2025 tables, continuing the annual update cadence.source
- The 2026 Gross to Net Income Conversion Table and Schedule of Basic Obligations took effect, published with the addendum dated March 13, 2026.source
Illinois child support FAQs
Does Illinois child support use gross or net income?
Net, but you rarely have to compute it yourself. Illinois publishes a standardized conversion table that turns monthly gross income into net using fixed tax assumptions, so most cases start from gross pay and let the table do the work. Parties can instead use an individualized net based on actual taxes. This calculator supports both entries.
What changed in the 2026 Illinois tables?
HFS updates the conversion table and the Schedule of Basic Obligations every year, and the 2026 versions were published with an addendum dated March 13, 2026. The dollar amounts in both tables shift with the annual update, so an estimate run on the 2025 tables can differ from the current numbers. This page uses the 2026 tables in full.
Why do 146 overnights matter so much in Illinois?
146 nights is 40 percent of the year, and it is the statutory trigger for shared physical care. Below it, the paying parent owes a straight income share of the basic obligation. At 146 or more for each parent, the obligation is multiplied by 1.5, cross-multiplied by parenting time, and offset. The switch happens all at once, so one extra overnight can change the payment by hundreds of dollars.
Does 50/50 parenting time mean no child support in Illinois?
Usually not. With equal time, the shared care offset still runs on the two incomes, and the parent with the higher net income generally pays the difference. Support only nets to zero when the incomes are close enough that the two cross-multiplied amounts match.
What is the minimum child support order in Illinois?
When the paying parent’s gross income is at or below 75 percent of the federal poverty guideline for one person, about $997.50 a month under the 2026 guideline, there is a rebuttable presumption of $40 a month per child, capped at $120 a month across all children in the case. A court can also set a zero order in specific situations, such as incarceration with no ability to pay.
What if the paying parent already pays support for another child?
Court-ordered support actually paid for children of other relationships comes off the paying parent’s net income before the schedule lookup, under 750 ILCS 5/505(a)(3)(F) and (G). The statute caps the deduction at the lesser of what is actually paid or 75 percent of a hypothetical guideline amount for those children.
Is there an official Illinois child support calculator?
Yes. HFS runs a Child Support Estimator on its website, with a guided mode and a direct-entry mode, and it is linked in the sources below. This page runs the same published tables and shows the intermediate steps, so you can see how the figure is built and check either tool against the other.
What happens when combined income is above the schedule?
The 2026 schedule tops out at $27,374.99 of combined monthly net income. Above that, the court sets support using its discretion, and the guideline amount at the top bracket serves as the floor. This calculator reports that the schedule does not cover such incomes rather than guessing a number.
Good to know in Illinois
- In re Marriage of Turk, 2014 IL 116730, held that even a custodial parent can be ordered to pay child support in the right circumstances, a principle that carried into the income shares era.
- In re Marriage of Rogers, 213 Ill. 2d 129 (2004), read "income" broadly, so recurring gifts and even some loans can count in the support calculation.
- When maintenance runs between the same parents, it is computed first: the amount is deducted from the payor’s net income and added to the recipient’s income before the child support math starts.
- Illinois reviews its guideline economics on the federal four-year cycle and refreshes the dollar tables annually, so expect new numbers each spring.
How to use this estimate
Enter each parent’s monthly gross income and let the tool run the official conversion table, the same one courts use for standardized net income. If you and the other parent have already computed or agreed on individualized net incomes, switch the mode and enter those instead; Illinois law accepts both.
Count overnights honestly. The formula cares about where the children actually sleep, and the 146-night line is a cliff, not a slope. If the paying parent is near 40 percent of the nights, run the number at 145 and again at 146 to see how much rides on the schedule.
The tool asks who pays each add-on because the answer changes the transfer. A child care bill the receiving parent pays increases the payment by the paying parent’s share; the same bill paid by the paying parent reduces it.
Treat the result as the guideline starting point. Illinois courts follow the tables unless someone shows a reason to deviate, and the HFS estimator linked below is the state’s own version of this arithmetic.
What this estimate includes
- The 2026 HFS gross-to-net conversion, with the majority and non-majority columns applied by parenting time
- The 2026 Schedule of Basic Obligations for 1 to 6 children, up to $27,374.99 combined net
- The 146-overnight shared physical care formula with the 1.5 multiplier and offset
- The $40 per child minimum order for gross income at or below 75 percent of the poverty guideline
- The deduction for court-ordered support actually paid for children of other relationships
- Child care and children’s health insurance add-ons, divided by income share with who-pays credit
What it leaves out
- Individualized net income arithmetic from your actual tax returns; enter that net yourself in net mode
- Maintenance between the parents, which is computed first and shifts both incomes (see the maintenance calculator)
- Extraordinary medical, school, and extracurricular expenses the court divides case by case
- Deviations, imputed income for voluntary unemployment, and other judgment calls
- Income above the top schedule bracket, where the court sets the number
Official sources
Official sources last verified: .
- 750 ILCS 5/505 (child support) and 5/504 (maintenance)
Illinois General Assembly (ilga.gov) Last checked
- 2026 Gross to Net Income Conversion Table (standardized tax amounts)
Illinois HFS Last checked
- 2026 Illinois Schedule of Basic Obligations
Illinois HFS Last checked
- 2026 Addendum (methodology; Venohr/CPR, dated 2026-03-13)
Illinois HFS Last checked
- HFS Income Shares hub (all guideline tables)
Illinois HFS Last checked
- HFS Child Support Estimator
Illinois HFS Last checked
Reviewed by SupportDecode Editorial Team Page content reviewed Sources Methodology Update log
Changelog: page first published with the full 2026 HFS conversion and obligation tables, the 146-overnight shared care formula, and the $40 per child minimum order. Material changes are dated in the update log.