Last updated: July 27, 2026
Wisconsin calculates child support using the Percentage of Income Standard set out in Chapter DCF 150 of the state’s administrative code. If one parent has the children fewer than 92 overnights a year, support is a flat percentage of the paying parent’s gross monthly income: 17% for one child, 25% for two, 29% for three, 31% for four, and 34% for five or more. If both parents have at least 92 overnights (25% of the year), the court switches to a shared-placement formula that runs both parents’ incomes through those percentages, multiplies each result by 150%, prorates each by the other parent’s share of overnights, and orders the parent with the higher figure to pay the difference.
That second formula — especially the 150% multiplier — is the step most online explanations skip, and it changes the math for every shared-placement family in the state. Here is how each piece works, with real numbers.
Estimate Your Payment First
Before reading the formulas, run your own numbers. Enter both incomes, the number of children, and your overnight schedule:
An estimate is not a court order. Only a judge or family court commissioner can set support, and courts can deviate from the guidelines when the standard result would be unfair to a parent or the child.
The Standard Percentages (Fewer Than 92 Overnights)
When one parent has primary placement and the other has the children less than 25% of the year, Wisconsin applies the standard percentages to the paying parent’s gross income — before taxes, not take-home pay:
| Children | Percentage of gross monthly income |
|---|---|
| 1 | 17% |
| 2 | 25% |
| 3 | 29% |
| 4 | 31% |
| 5 or more | 34% |
Example: a parent earning $2,500 a month with one child pays $2,500 × 17% = $425 per month.
Gross income is broader than a paycheck. It includes wages, salary, commissions, bonuses, self-employment income, unemployment and worker’s compensation, and most other regular income sources. If a court finds a parent is voluntarily unemployed or earning less than they reasonably could, it can base support on earning capacity instead of actual earnings — what Wisconsin calls imputed income.
Wisconsin’s flat-percentage model is also increasingly rare. Most states now combine both parents’ incomes in an income-shares calculation — see how the Michigan Child Support Formula works for the contrast — while Mississippi is one of the few states that, like Wisconsin, still applies a flat percentage to one parent’s income.
The Shared-Placement Formula, Step by Step (92+ Overnights Each)
When each parent has the children at least 92 overnights a year, both parents’ incomes enter the calculation. The state’s shared-placement worksheet walks through four steps:
- Multiply each parent’s gross monthly income by the standard percentage for the number of children.
- Multiply each result by 150%. The multiplier reflects that two households are both maintaining bedrooms, food, clothing, and transportation for the same children.
- Multiply each parent’s figure by the percentage of the year the children spend with the other parent (overnights ÷ 365).
- Subtract the smaller amount from the larger. The parent with the higher figure pays the difference.
Worked example with two children — Parent A earns $2,000 a month with 219 overnights; Parent B earns $3,000 a month with 146 overnights:
- Parent A: $2,000 × 25% = $500 → × 150% = $750 → × 40% (146/365) = $300
- Parent B: $3,000 × 25% = $750 → × 150% = $1,125 → × 60% (219/365) = $675
- Parent B pays Parent A: $675 − $300 = $375 per month
Two things surprise people here. First, a 50/50 schedule does not mean zero support — if incomes differ, the higher earner still pays the offset. Second, every added overnight shifts the proration in step 3, which is why placement schedules and support amounts get negotiated together.
High-Income and Low-Income Adjustments
The flat percentages bend at both ends of the income scale.
High-income payers. Above $7,000 in gross monthly income ($84,000 a year), lower marginal percentages apply to the income in each bracket:
| Monthly income tier | 1 child | 2 | 3 | 4 | 5+ |
|---|---|---|---|---|---|
| First $7,000 | 17% | 25% | 29% | 31% | 34% |
| $7,000–$12,500 | 14% | 20% | 23% | 25% | 27% |
| Over $12,500 | 10% | 15% | 17% | 19% | 20% |
Low-income payers. A parent earning roughly between 75% and 150% of the federal poverty guidelines pays under a reduced schedule that phases the percentages up gradually, so the order leaves enough for basic living expenses. The dollar cutoffs adjust as poverty guidelines change, so check the current schedule published by the Wisconsin Department of Children and Families before relying on a specific figure.
Situations Most Calculators Ignore
Three scenarios fall outside the basic formulas, and most online calculators simply do not handle them.
Serial-family payers. A parent who already has a legal support obligation for children from another relationship subtracts that obligation from gross income before the percentage is applied to the new case. Order matters: the earlier obligation is calculated first.
Split placement. When parents have two or more children and each parent has primary placement of at least one child, the percentages are prorated per child (for two children, 12.5% each) and the two obligations are offset against each other.
Combined situations. A family can be shared-placement for one child and split for another, or serial-family and high-income at once. The state publishes separate worksheets for these combinations, and this is where a self-help estimate stops being reliable and case-specific advice earns its cost.
What the Payment Covers — and What Gets Added on Top
The guideline amount covers basic support: housing, food, clothing, transportation, and ordinary personal expenses. Variable costs — child care, health insurance premiums, uninsured medical expenses, tuition, and a child’s special needs — are handled separately, typically divided between the parents in proportion to income and written into the order as their own line items. If you compare offers in a negotiation, compare the whole package, not just the guideline number. For a full breakdown of which expenses live inside the base payment and which get split separately, see what child support covers vs. what it does not.
If you are starting a case or heading back to court to modify an order without a lawyer, two resources can save you real money before you ever pay a retainer. The book Navigating Child Support walks through how support really gets set, enforced, and changed from a parent’s point of view, and the companion site at forms.navigatingchildsupport.com organizes the worksheets and court forms you will actually need to file.
Frequently Asked Questions
Is Wisconsin child support based on gross or net income? Gross income — the percentages apply before taxes and most deductions, not to take-home pay.
Do you pay child support with 50/50 placement in Wisconsin? Usually yes, if incomes differ. The shared-placement formula offsets the two obligations, so the higher earner pays the difference even at exactly 182.5 overnights each.
How much is child support for one child in Wisconsin? Under the standard guideline, 17% of the payer’s gross monthly income — $425 on a $2,500 monthly income — subject to the shared-placement, high-income, and low-income adjustments above.
Can the court order something other than the guideline amount? Yes. The percentages are the starting point, and a judge can deviate after weighing factors like the child’s needs, each parent’s earning capacity, and the cost of health care and child care.
This article is general information, not legal advice. Child support rules change and courts apply them to specific facts, so confirm current figures with the Wisconsin Department of Children and Families and consult a licensed Wisconsin family law attorney about your own case.
