How Wisconsin Calculates Child Support
Wisconsin uses the Percentage of Income model for child support. The governing law is Wisconsin Statutes Section 767.511. Wisconsin applies a fixed percentage of the paying parent's gross monthly income based on the number of children covered by the order. The receiving parent's income is not part of the base calculation.
Wisconsin's approach is one of the most direct child support formulas in the country. The paying parent's gross income is multiplied by a set percentage. No schedule table is needed. No combined income calculation is required for the base obligation.
The Wisconsin Child Support Formula
Wisconsin's calculation follows two steps for the base obligation.
Step one is identifying the paying parent's gross monthly income. Step two is multiplying that figure by the applicable percentage based on the number of children.
Wisconsin's percentages under Section 767.511 are:
- 1 child: 17 percent of gross monthly income
- 2 children: 25 percent
- 3 children: 29 percent
- 4 children: 31 percent
- 5 or more children: 34 percent
A practical example: the paying parent earns $5,000 per month gross. There are two children. The obligation is 25 percent of $5,000, which is $1,250 per month. The receiving parent's income does not change this base result.
Wisconsin applies its percentages to gross income, income before taxes and before any deductions. There is no net income conversion in the standard Wisconsin formula.
What Counts as Income in Wisconsin
Wisconsin courts include wages, salaries, commissions, bonuses, overtime, self-employment income, rental income, pension and retirement distributions, Social Security benefits, SSDI payments, unemployment compensation, workers' compensation, and income from any other regular source.
Courts can impute income to a paying parent who is voluntarily unemployed or underemployed based on work history, education, skills, and local employment conditions.
For self-employed paying parents, Wisconsin uses gross business income less ordinary and necessary business expenses as the gross income figure.
Wisconsin allows certain deductions from gross income before applying the percentage: court-ordered child support being paid for children from other relationships. This prevents multiple support orders from compounding unfairly.
The Wisconsin Shared Placement Adjustment
Wisconsin has a specific calculation for shared placement situations. When each parent has at least 25 percent of physical placement time, approximately 91 days or overnights per year, Wisconsin applies a shared placement formula that reduces the standard percentage obligation.
The shared placement formula works in two steps. First, the standard percentage obligation is multiplied by 1.5 to create a shared placement base. Second, that figure is multiplied by the other parent's percentage of placement time to determine what that parent owes. Both parents' obligations are calculated using this method. The parent with the higher calculated obligation pays the net difference to the other parent.
The 1.5 multiplier reflects Wisconsin's recognition that shared placement is more expensive than sole placement. Each parent maintains a home fully equipped for the children, resulting in duplicated household costs. The multiplier accounts for that reality before the obligations are offset.
A practical example at shared placement: Parent A earns $5,000 per month. Parent B earns $3,000 per month. Each parent has 50 percent placement. Standard obligation for two children: 25 percent. Parent A's shared placement base: $5,000 × 25% × 1.5 = $1,875. Multiplied by Parent B's placement share of 50 percent: $937. Parent B's shared placement base: $3,000 × 25% × 1.5 = $1,125. Multiplied by Parent A's placement share of 50 percent: $562. Parent A's net obligation: $937 minus $562 = $375 per month to Parent B.
Step-by-Step: How to Use This Calculator
Step 1. Identify the paying parent's gross monthly income. Include wages, self-employment gross profit less expenses, rental income, and any other regular income. Subtract any court-ordered child support you are paying for children from other relationships.
Step 2. Identify the number of children covered by this order.
Step 3. Count your placement days per year. If each parent has at least 25 percent of placement time, approximately 91 days or overnights, the shared placement formula applies. Enter your percentage by dividing placement days by 365.
Step 4. Multiply gross income by the applicable percentage for the base obligation, or review the shared placement calculation if that formula applies.
Step 5. Add healthcare costs. Wisconsin courts add the children's health insurance premium on top of the base obligation.
Step 6. Enter the receiving parent's income if you are near or above the shared placement threshold. The shared placement formula requires both parents' gross incomes.
Step 7. Review the result and confirm which formula was applied.
Parenting Time Adjustments in Wisconsin
Below 25 percent of placement time for the paying parent, the standard percentage formula applies with no automatic credit. At 25 percent and above for each parent, the shared placement formula applies.
The 25-percent threshold is a firm line. Moving from 24 to 25 percent triggers a fundamentally different calculation. The difference in monthly obligations between the standard formula and the shared placement formula can be substantial, particularly when one parent earns significantly more than the other.
Wisconsin courts have discretion to deviate from both the standard and shared placement formulas when the result would be unfair given the specific circumstances of the case.
Add-On Expenses in Wisconsin
Wisconsin courts add the children's health insurance premium and work-related childcare costs to the base obligation. Extraordinary medical expenses and educational costs may also be addressed through the court order on a case-by-case basis.
Reading Your Results
The results show the paying parent's gross monthly income, the applicable percentage, whether the standard or shared placement formula was used, the 1.5 multiplier calculation if shared placement applies, each parent's gross income at shared placement, the net obligation, add-on costs, and the final monthly total.
Confirm which formula was applied. If your placement days are near 91, a few days in either direction determines whether the standard or shared placement calculation governs, and the financial difference between those two outcomes can be significant.
After You Get Your Estimate
Wisconsin courts follow Section 767.511 in all standard cases. Deviation is allowed when the guideline amount would be unfair or unjust. Courts consider both parents' financial resources, the child's needs, the placement arrangement, and any extraordinary circumstances.
Modification in Wisconsin requires a substantial change in circumstances. A 15 percent or more change in the calculated obligation is a commonly applied benchmark. Income changes, shifts in placement time past the 25-percent shared placement threshold, and changes in healthcare costs are the most common grounds.
A licensed Wisconsin family law attorney can help you verify which formula applies and advise on modification options. Many offer a free initial consultation.