How is Child Support Calculated in Wisconsin?

Wisconsin does not combine both parents' incomes the way many states do. Instead, it applies a flat percentage to the paying parent's gross income alone — 17% for one child, up to 34% for five or more. This is called the Percentage of Income Standard, and it is set out in Wis. Admin. Code DCF 150. When both parents share placement closely, a different formula takes over that looks at both incomes and both households.

The Percentage of Income Standard: how it's different from most states

Many states — Tennessee and Ohio, for example — use an Income Shares Model, which combines both parents' incomes into one household-style budget before splitting the obligation. Wisconsin takes a simpler approach for cases where one parent has the child most of the time: it looks only at the paying parent's gross income and applies a set percentage based on the number of children.

This standard applies under Wis. Stat. §767.511, which gives courts the authority to order support consistent with the percentage standards established by the Department of Children and Families. The percentage is applied to the paying parent's income only when the other parent has primary physical placement — meaning the child lives with them the clear majority of the time. Once placement is closer to equal, Wisconsin switches to a separate shared-placement formula covered further down.

How Wisconsin defines income for child support

Wisconsin's guidelines use a broad definition of gross income — most money coming in before taxes and payroll deductions counts.

Income type	Included?
Wages, salaries, commissions, bonuses, tips	Yes
Self-employment income	Yes — gross revenue minus ordinary and necessary business expenses
Overtime and second-job earnings	Yes
Rental and investment income	Yes — net rental income, dividends, and interest
Pension, retirement, and disability benefits	Yes
Social Security benefits	Yes, with specific treatment for a child's derivative benefit
Means-tested public assistance (SNAP, W-2, Medicaid)	Excluded — not counted as income

The percentage table: how many children, how much of your income

Once gross income is established, the standard percentage is applied directly to it. These are the base rates under DCF 150 for a paying parent with primary-placement obligations.

Number of children	Percentage of gross income
1 child	17%
2 children	25%
3 children	29%
4 children	31%
5 or more children	34%

Worked example — one child, primary placement with one parent

High-income and low-income adjustments

Applying a flat 17%–34% rate to very high income can produce a number far beyond what a child actually needs. To address this, Wisconsin treats gross income above $84,000 a year (about $7,000 a month) as a high-income case under DCF 150's high-income payer standard. Courts use a separate worksheet that applies reduced percentages to income above that threshold, rather than the standard rate straight through — the goal is a support amount tied to the child's needs and the family's established standard of living, not a runaway percentage of a high earner's paycheck.

At the other end, Wisconsin's guidelines also account for parents with limited income, including adjustments that consider a parent's ability to pay while still meeting their own basic needs. A minimum support order may still apply even at very low income levels, so an obligation of some kind is generally set even when resources are tight.

Shared placement: when both parents have at least 25% of overnights

This is where Wisconsin's system looks the most different from a standard support order. When both parents have court-ordered placement of at least 25% of overnights a year — roughly 92 nights — Wisconsin applies the shared-placement formula under DCF 150.04(6) instead of the flat percentage above.

The shared-placement formula runs in a few steps. Each parent's monthly income available for support is multiplied by the percentage standard that matches the number of children. That result is then multiplied by 150% — an adjustment meant to account for the added cost of maintaining two homes with duplicated basics like bedrooms, clothing, and everyday items for the child. Each parent's adjusted amount is then reduced based on their own share of overnights, since the parent caring for the child is treated as spending that portion directly. The two resulting figures are compared, and the parent with the larger obligation pays the difference to the other parent.

Worked example — shared placement

Variable costs: child care, tuition, and special needs

The percentage-based support amount is meant to cover a child's everyday living costs — food, housing, clothing. It does not automatically include larger, specific costs. Wisconsin calls these "variable costs," defined to include child care, tuition, a child's special needs, and other activities involving substantial cost.

Courts assign responsibility for variable costs in proportion to each parent's share of placement, based on a documented list the parents provide. If placement is 70/30, the parent with 70% of the time generally covers 70% of the variable costs, and the other parent covers 30%. These costs are typically addressed separately from the base support order and can be revisited as expenses change — a child starting a costly extracurricular activity or needing specialized therapy, for example.

When courts deviate from the standard

Wisconsin treats the percentage standard as the presumptive starting point, but courts can deviate from it — up or down — when applying the straight percentage would be unfair to the child or one of the parents. Common deviation factors include the child's special physical, emotional, or educational needs, a significant income disparity between households, the child's age, and whether a parent is already supporting other children from a different relationship (sometimes called a serial-family situation). A deviation requires the court to state its reasoning on the record rather than simply picking a different number.

For a broader look at Wisconsin divorce finances, including how property and spousal support are handled, see the Wisconsin divorce finances overview. We also have a companion guide on how spousal maintenance is calculated in Wisconsin, including the 10 statutory factors judges weigh.

Common questions about Wisconsin child support

How is child support calculated in Wisconsin? Wisconsin applies a flat percentage to the paying parent's gross income under the Percentage of Income Standard — 17% for one child, 25% for two, 29% for three, 31% for four, and 34% for five or more. This applies when one parent has primary placement. A separate shared-placement formula takes over once both parents have at least 25% of overnights.

How does shared placement change the calculation? Once both parents have 25% or more of overnights each (about 92 nights a year), Wisconsin uses the shared-placement formula. Each parent's income is run through the percentage standard, multiplied by 150% to account for duplicated household costs, and then adjusted for each parent's own share of overnights. The difference between the two results becomes the monthly payment.

What counts as income for Wisconsin child support? Wages, salaries, bonuses, commissions, self-employment income, overtime, rental and investment income, pensions, and disability benefits generally count. Means-tested public assistance does not. If a parent is voluntarily unemployed or underemployed, a court may impute income based on earning capacity. For a broader explanation of income shares versus percentage-based models, see our general guide on how child support is calculated.

Can Wisconsin child support be modified? Yes, when there has been a substantial change in circumstances — a significant income change, a new placement schedule, or enough time passing since the last order. A parent should not reduce or stop payments informally; the change needs to go through the court to be enforceable. For more on the modification process generally, see our guide on child support modification.