How to Calculate Child Support in Wisconsin: Percentages and Adjustments

To calculate child support in Wisconsin, start with the paying parent’s gross monthly income and multiply it by a fixed percentage tied to the number of children: 17% for one child, 25% for two, 29% for three, 31% for four, and 34% for five or more.¹ A parent earning $4,000 a month with two children owes $1,000 under the base formula. The percentage standard, set out in Wisconsin Administrative Code Chapter DCF 150 and Wisconsin Statute 767.511, applies the same way whether the parents were married or not. What changes the number is how much time each parent spends with the child, whether either parent already supports children from another relationship, and where the paying parent’s income falls on the state’s earnings scale.

What Counts as Gross Monthly Income

The formula is only as accurate as the income figure you plug into it, and Wisconsin defines gross income broadly under DCF 150.02(13). It starts with salary and wages, then adds investment interest, commissions, Social Security disability benefits, worker’s compensation, unemployment insurance, veterans disability compensation (including military housing and food allowances), and voluntary deferred compensation such as 401(k) contributions.² If a parent owns enough of a closely held corporation or partnership to control the business or access its earnings, undistributed income from that entity counts too.

A short list of income is excluded: child support received from another case, Supplemental Security Income (SSI), food stamps, foster care and kinship care payments, and other public assistance benefits.² Most government benefits don’t reduce the obligation unless they fall into one of those categories.

Expect to document income with recent pay stubs and your most recent federal and state tax returns. Wisconsin circuit courts offer a Financial Disclosure Statement (Form FA-4139V) for laying out assets, liabilities, income, and expenses, though the form itself is voluntary.³ The court can consider all relevant financial information when setting the amount.⁴

The Standard Percentage Formula

When one parent has primary physical placement and the other has the child less than 25% of the time, Wisconsin applies the percentage of income standard straight through:¹

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

These percentages are a presumption. The court follows them unless a parent shows the result would be unfair to the child or either party, at which point the judge weighs the deviation factors in Wis. Stat. 767.511(1m).⁴

Adjustments for High Earners

Parents earning more than $7,000 per month ($84,000 a year) have the percentage reduced on income above that threshold. The standard rate applies to the first $7,000. Income between $7,000 and $12,500 is calculated at a lower rate, and income above $12,500 drops further:¹

1 child: 17% on the first $7,000, 14% on $7,000–$12,500, 10% above $12,500
2 children: 25%, 20%, 15%
3 children: 29%, 23%, 17%
4 children: 31%, 25%, 19%
5 or more: 34%, 27%, 20%

For a parent earning $15,000 a month with one child, the math is $1,190 on the first $7,000 (17%), $770 on the next $5,500 (14%), and $250 on the remaining $2,500 (10%), for a total of $2,210. The declining rates keep support from scaling indefinitely with income, but the dollar figure still climbs with earnings.

Adjustments for Low Earners

At the other end of the scale, the percentage drops for parents earning between 75% and 150% of the federal poverty guidelines. Appendix C of DCF 150 publishes a graduated schedule that reduces the effective rate as income falls.⁵ At the lowest tier, a parent with one child earning up to roughly $998 per month pays about 11.22% rather than the standard 17%. Parents earning below 75% of the federal poverty level may have the obligation set lower still, or at a nominal amount, depending on the court’s assessment.

When Both Parents Share Placement

Once both parents have the child for at least 25% of the year (at least 92 overnights annually), the straight percentage no longer applies. Wisconsin switches to the shared-placement formula.⁶ The arithmetic is longer, but the logic is this:

Calculate each parent’s hypothetical obligation as if they were the sole payer, using the standard percentages.
Multiply each amount by 1.5. The 150% multiplier accounts for both households maintaining a home equipped for the child, with duplicate costs for housing, furniture, and basic supplies.
Weight each multiplied amount by the percentage of time the child spends with the other parent.
Subtract the smaller weighted obligation from the larger. The difference is what the higher-earning parent pays.

Even in a 50/50 placement arrangement, a parent who earns substantially more than the other can still owe a meaningful monthly amount. The shared-placement formula only applies when the placement order itself specifies at least 25% time with each parent.

Credit for Supporting Other Children

A parent who already pays court-ordered child support for children from a prior relationship gets a serial-payer adjustment. The court subtracts the existing support order from gross income first, then applies the percentage to the reduced figure for the new case.⁷ Only existing court orders count. Informal or voluntary support to a child without a court order will not be subtracted. When the parent also has shared placement in the new case, the serial-payer rules and the shared-placement formula interact, adding another layer to the calculation.

Income the Court Assigns to You

A parent who quits a job or deliberately takes lower-paying work to shrink the obligation can be assigned income they aren’t actually earning. Under DCF 150.03(3), if a parent is voluntarily unemployed or underemployed without good cause, the court may impute income based on earning capacity.⁸ The court looks at recent work history, past earnings, education and job skills, barriers to employment such as homelessness or lack of a driver’s license, and whether the parent has been actively looking for work.

Two protections matter here. Incarceration cannot be treated as voluntary unemployment for purposes of setting or modifying support.⁸ A parent who stays home to care for a child with unusual physical or emotional needs may also have good cause for reduced employment.

When the Guidelines Can Be Set Aside

The percentage standard is a presumption, not a ceiling or a floor. Either parent can ask the court to set a different amount if the standard calculation would be unfair. Wis. Stat. 767.511(1m) lists the factors a judge weighs:⁴

The child’s own financial resources, such as a trust or assets held for the child
Both parents’ financial resources, including assets beyond income
Maintenance (alimony) paid or received by either parent
Each party’s needs and debts
Childcare and education costs, including day care and private school
The child’s physical and emotional health needs
Tax consequences for each parent

The parent requesting the deviation carries the burden. A general feeling that the number is too high will not move a court. Specific evidence tying the standard result to an unfair outcome is what matters.

Health Insurance and Expenses the Base Number Doesn’t Cover

The base support figure covers day-to-day costs like food, clothing, and shelter. It doesn’t cover everything. Wis. Stat. 767.513 requires the court to separately assign responsibility for the child’s health care expenses in every support order.⁹ The court looks at who already has the child covered, what coverage is available through each parent’s employer, and what the premiums cost. One or both parents can be ordered to carry insurance for the child, and that payment can be collected through income withholding like the base amount.

Uninsured medical expenses, dental work, childcare, and educational costs are handled case by case. If you expect significant recurring expenses, such as ongoing therapy or specialized schooling, raise them at the initial hearing rather than coming back later to modify the order.

Running the Numbers Before You File

The Wisconsin Department of Children and Families publishes worksheets and an online calculator covering the percentage standard, the shared-placement formula, and the serial-payer calculation.¹⁰ Working through them with your actual income figures and placement schedule produces a realistic estimate and flags disputes before the hearing. If the result surprises you, check your gross income definition first: that single input drives the entire calculation, and it is the one most people get wrong on the first try.

1
Wisconsin Department of Children and Families. Your Guide to Setting Support Amounts
2
Wisconsin State Legislature. Wisconsin Administrative Code DCF 150.02
3
Wisconsin Court System. Form FA-4139V Financial Disclosure Statement
4
Wisconsin State Legislature. Wisconsin Statutes 767.511
5
Wisconsin State Legislature. Wisconsin Administrative Code DCF 150 Appendix C
6
Wisconsin Department of Children and Families. Shared-Placement Worksheet to Estimate Support
7
Wisconsin State Legislature. Wisconsin Administrative Code DCF 150.04
8
Wisconsin Department of Children and Families. DCF 150 Child Support Guidelines Quadrennial Review
9
Wisconsin State Legislature. Wisconsin Statutes 767.513
10
Wisconsin Department of Children and Families. Tools to Estimate Income and Support Amounts