How to Calculate Child Support in Wisconsin: Percentages and Placement

To calculate child support in Wisconsin, start with the paying parent’s gross monthly income and multiply it by a fixed percentage based on the number of children: 17% for one child, 25% for two, 29% for three, 31% for four, and 34% for five or more.¹ That baseline shifts when parents share placement, when income is unusually high or low, or when the paying parent already supports children from an earlier relationship. Only a court can issue a binding order, but the formula is public and you can run the numbers yourself before you walk into one.

What Counts as Gross Income

The percentages apply to gross income, meaning everything you earn before taxes and deductions. Wisconsin defines this broadly. Wages, salary, bonuses, commissions, investment and interest income, Social Security disability and retirement benefits, unemployment insurance, worker’s compensation payments meant to replace income, and income continuation benefits all count. So does undistributed business income the court decides isn’t genuinely needed to run the business.²

A few things are left out: child support you receive for other children, public assistance, foster care payments, and kinship care payments.²

If you own a business or work for yourself, the court can subtract legitimate expenses needed to produce the income, but it will add back wages paid to dependent household members and any retained earnings it finds unnecessary for the business. The burden sits with you to show those retained earnings are genuinely needed.¹

The Standard Percentages

These are the base rates applied to monthly gross income:¹

1 child: 17%
2 children: 25%
3 children: 29%
4 children: 31%
5 or more children: 34%

These apply in their full form when one parent has primary placement and the other parent has fewer than 92 overnights per year. A parent earning $5,000 per month in gross income with two children in the other parent’s primary placement has a baseline obligation of $1,250 (25% of $5,000). That number is only the starting point. The adjustments below change it for most real cases.

Shared Placement

When each parent has the children for at least 25% of the year, which works out to 92 or more overnights, Wisconsin uses a shared-placement formula that pulls in both parents’ incomes and the time split. The math runs through four steps:³

Multiply each parent’s monthly income by the standard percentage for the number of children.
Multiply each result by 1.5. This 150% multiplier accounts for the fact that both households are now paying to keep a home for the children.
Multiply each parent’s adjusted figure by the percentage of time the children spend with the other parent.
Subtract the smaller number from the larger. The parent with the higher number pays the difference.

A worked example: Parent A earns $5,000 and has the children 60% of the time; Parent B earns $3,500 and has them 40% of the time. With two children, Parent A’s basic support is $1,250 and Parent B’s is $875. After the 1.5 multiplier, those become $1,875 and $1,312.50. Parent A’s share goes to the other parent’s time (40%), so $1,875 × 0.40 = $750. Parent B’s share goes to the other parent’s time (60%), so $1,312.50 × 0.60 = $787.50. Parent B owes the difference: $37.50 per month. Small changes in overnight counts move the result noticeably because the time share runs through both halves of the calculation.

Split Placement

Split placement applies when there are two or more children and each parent has primary placement of at least one child. The court prorates the per-child percentage rather than using the standard figures:⁴

2 children: 12.5% per child
3 children: 9.67% per child
4 children: 7.75% per child
5 children: 6.8% per child

Each parent owes the per-child rate for every child placed with the other parent. The two totals are offset, and the higher-owing parent writes the check for the difference.

High-Income Payers

Once monthly gross income passes $7,000, Wisconsin reduces the percentages on the income above that line. The formula uses three tiers:⁵

First $7,000 per month: standard rates (17/25/29/31/34%).
$7,001 to $12,500 per month: 14% for one child, 20% for two, 23% for three, 25% for four, 27% for five or more.
Above $12,500 per month: 10% for one child, 15% for two, 17% for three, 19% for four, 20% for five or more.

A parent earning $15,000 per month with one child owes 17% of the first $7,000 ($1,190), 14% of the next $5,500 ($770), and 10% of the remaining $2,500 ($250), for a total of $2,210 per month. Applying 17% straight across would have produced $2,550.

Low-Income Payers

At the other end, when a parent’s income falls between 75% and 150% of the federal poverty guidelines, Wisconsin uses a separate schedule that phases the percentages in gradually. A parent earning around $998 per month would owe roughly 11.22% for one child, or about $112, instead of the standard $170. By the time income reaches about $2,031 per month, the full percentages apply. The Department of Children and Families updates this schedule every year as federal poverty figures change.⁶

If You Already Pay Support for Another Child

A serial family payer is a parent who already has a court-ordered support obligation from a prior relationship. Wisconsin subtracts that existing obligation from gross income before applying the percentage for the new order.² If you earn $4,000 per month and already pay $680 for one child from an earlier relationship, the court calculates the new obligation on $3,320. For one new child, 17% of $3,320 comes to about $564.⁷

When a Parent Isn’t Working at Full Capacity

If a parent is voluntarily unemployed or deliberately working below their earning capacity, the court can assign them an income based on what they could reasonably make. In setting that figure, judges look at education, job skills, recent work history, previous earnings, physical and mental health, time as a primary caretaker, criminal record, and the local job market.¹ They also consider barriers like homelessness, lack of a driver’s license, substance dependence, and immigration status.

Incarceration is not treated as voluntary unemployment. A court setting or modifying support cannot impute income to an incarcerated parent based on what they used to earn.¹

When no reliable income information is available despite real efforts to find it, the court can impute income based on 10 to 35 hours per week at the higher of the federal or state minimum wage.⁸

Health Insurance Adjustments

Wisconsin child support orders usually include a medical support component. A court can order one or both parents to add the children to employer-provided health coverage, as long as the added cost does not exceed 10% of that parent’s monthly income or another amount the court sets.⁹

The support amount then gets adjusted. If the paying parent carries the policy, the court can reduce support to offset the premium. If the receiving parent carries it, support can be increased so the paying parent covers a share. The adjustment is set as a flat dollar amount or a percentage of the premium.⁹

When Courts Depart from the Formula

Either parent can ask the court to set support higher or lower than the calculated amount. The judge can grant a deviation if the standard figure would be unfair to the child or to a parent. Wisconsin statute lists more than a dozen factors the court weighs, including the financial resources of the child and each parent, maintenance paid or received, other legal dependents, the standard of living the child would have had if the parents stayed together, child care costs, extraordinary travel costs for placement, health needs, educational needs, tax consequences, each parent’s earning capacity, and the best interests of the child.¹⁰ The list is open-ended, so the court can weigh any other factor it finds relevant.

Deviations tend to succeed when the numbers tell a clear story: a child whose special-needs expenses dwarf the formula amount, or a paying parent whose real resources far exceed what shows up as income.

Running the Numbers Yourself

The Department of Children and Families publishes free worksheets for every version of the calculation: standard, shared placement, split placement, serial family, high income, and low income.⁴ You enter each parent’s gross income, the number of children, and the placement schedule, and the worksheet applies the right formula.

The result is an estimate. Only a court can set a binding order. But the worksheets use the same formulas the court applies, so running your situation through the right one before a hearing is the best way to see what the standard calculation will produce and to catch errors in any proposed order. If your case stacks multiple adjustments on top of each other, say shared placement plus a prior obligation plus income above $7,000, work through each layer separately so you can see where each dollar of the final number comes from.

1
Wisconsin State Legislature. Wisconsin Administrative Code – Chapter DCF 150 Child Support Standard
2
Wisconsin Administrative Code. Wisconsin Code DCF 150 – Child Support Standard
3
Wisconsin Department of Children and Families. Shared-Placement Worksheet to Estimate Support Under DCF 150
4
Wisconsin Department of Children and Families. Tools to Estimate Income and Support Amounts
5
Wisconsin Department of Children and Families. High-Income Payer Worksheet to Estimate Support
6
Wisconsin State Legislature. Wisconsin Administrative Code – Chapter DCF 150 Appendix C
7
Wisconsin State Legislature. Wisconsin Administrative Code DCF 150.04(6)(b)
8
Wisconsin Department of Children and Families. DCF 150 Imputation of Income Guidance
9
Wisconsin Department of Children and Families. Medical Support Orders
10
Wisconsin State Legislature. Wisconsin Statutes Marriage and Family 767.511