Wisconsin uses a formula based on both parents' income
Wisconsin does not set a flat dollar amount for child support. Instead, the state uses an income shares model, which means the court calculates what percentage of each parent's income should go toward the child's care, then divides that obligation between both parents based on their earnings.
The basic calculation starts with each parent's gross monthly income — wages, self-employment earnings, bonuses, rental income, and certain benefits all count. The court then applies a percentage based on how many children are involved. For one child, the combined parental income up to a certain threshold is subject to 17 percent of that income going to child support. For two children, it is 25 percent; for three, 29 percent; for four, 31 percent; for five or more, 34 percent.
Each parent pays their share of that total obligation based on what portion of the combined income they earn. If one parent earns 60 percent of the combined income and the other earns 40 percent, the first parent pays 60 percent of the calculated support amount.
Key Takeaways
- Wisconsin calculates child support as a percentage of combined parental income, ranging from 17 percent for one child to 34 percent for five or more children.
- Both parents' gross income — including wages, self-employment, bonuses, and certain benefits — counts toward the calculation.
- The income threshold that triggers the percentage changes yearly; amounts above that threshold may be calculated differently or not included at all.
- Custody arrangements, childcare costs, health insurance premiums, and other children in the household can all adjust the final amount up or down from the base calculation.
- The paying parent's obligation typically continues until the child turns 18, or 19 if still in high school.
Income thresholds and how they affect the amount
Wisconsin sets an income cap each year — the maximum amount of combined parental income subject to the percentage calculation. For 2024, that cap is $250,000 per month in combined income. Income above that threshold is not automatically included in the calculation, though a judge can order support on income above the cap if circumstances warrant it.
This means if two parents earn a combined $300,000 per month, only $250,000 is subject to the 17, 25, or 29 percent calculation. The remaining $50,000 may or may not factor into the final order, depending on what the judge decides.
The threshold amount changes each January based on inflation. If you are looking at an older order or estimate, check the current year's threshold with the Wisconsin Department of Children and Family Services or your local child support agency, because using an outdated number will give you an inaccurate picture.
Adjustments that raise or lower the base amount
The percentage-based calculation is a starting point, not always the final number. Wisconsin law allows judges to adjust support up or down based on several factors. The most common adjustments involve childcare costs (the paying parent's share of work-related childcare is added to their obligation), health insurance premiums (the cost of covering the child is split between parents), and custody time (if the paying parent has the child overnight more than 25 percent of the time, their obligation decreases).
Other reasons a judge might adjust the amount include extraordinary medical or dental expenses, the child's special needs, either parent's other children from different relationships, and whether either parent receives Social Security or other income that should not be counted. A parent's education or job training can also factor in — if one parent is in school full-time, a judge may temporarily reduce their obligation.
These adjustments happen during the initial court order or when someone requests a modification. They are not automatic; the parent seeking the adjustment usually has to ask for it and show why it applies.
How custody time affects what you pay
If the parent owing support has the child overnight 25 percent of the time or less, the calculation proceeds as described above. But if they have overnight custody more than 25 percent of the time, their support obligation decreases because they are directly covering some of the child's living expenses during their time.
Wisconsin calculates this by reducing the paying parent's income obligation proportionally. If a parent has the child 40 percent of the time instead of 10 percent, their share of the support obligation drops. The exact reduction depends on the income calculation and the specific custody arrangement, so the numbers vary case to case.
Overnight custody is what counts — daytime visits or weekday pickups do not trigger this adjustment. The court looks at the actual overnight schedule in the custody order or, if there is no formal order, the pattern that has been in place.
When the amount changes and how to request a modification
A child support order stays in place until the child turns 18, or 19 if they are still enrolled in high school full-time. Either parent can request a modification (a change to the amount) if circumstances have changed significantly — a job loss, a major increase in income, a change in custody, or a substantial change in childcare costs.
Wisconsin law says you can request a modification if the amount would change by 10 percent or more based on current income, or if there has been a substantial and continuing change in circumstances. You file a motion with the court that issued the original order, usually through your local child support agency or with an attorney.
The process typically takes several weeks to a few months. During that time, the current order remains in effect — you still owe the amount stated in the existing order until a judge signs a new one. If the new calculation is lower and you have been overpaying, you may receive a credit; if it is higher, your payments increase going forward.
Documents and information you need to know the amount
To calculate what child support would be in Wisconsin, you need both parents' gross monthly income (pay stubs, tax returns, or self-employment records), the number of children, the custody arrangement, and any childcare or health insurance costs. If you are trying to estimate what an order might be, you can use the Wisconsin Department of Children and Family Services online calculator, which walks through the formula step by step.
If a court order already exists, the amount is written in that order. You can find it through your local child support agency or by requesting it from the court that issued it. If you are in a dispute or modification process, both parents' most recent tax returns and current pay stubs are usually required as proof of income.
Frequently Asked Questions
Does child support in Wisconsin include college expenses?
No. Wisconsin child support ends when the child turns 18 or 19 if still in high school. College costs are not included in the standard child support calculation. A parent can ask a judge to order college support as part of a custody or divorce case, but it is not automatic and depends on the judge's decision.
What if one parent is self-employed or has irregular income?
Self-employment income counts toward the calculation. The court usually looks at tax returns from the past two years to average the income, because self-employed earnings fluctuate. If someone is newly self-employed or income has changed dramatically, a judge may use recent profit-and-loss statements or other documentation instead of old tax returns.
Can child support be waived or reduced to zero?
Not automatically. Both parents have a legal duty to support their children. A judge can reduce support if circumstances truly warrant it — for example, if the paying parent has no income and no ability to earn — but zero support requires a specific court order. The parent seeking the reduction must ask the court and show why it is appropriate.
What happens if income goes up significantly after the order is signed?
The order stays the same until someone requests a modification. If the paying parent's income rises substantially, the other parent can file for an increase. If the receiving parent's income rises, the paying parent can file for a decrease. Either way, you need to go back to court and show the change in circumstances.
Is child support the same in every Wisconsin county?
The calculation method is the same statewide — Wisconsin uses one formula. However, judges have discretion in how they apply adjustments and what they consider "substantial" circumstances for a modification. The practical outcome can vary slightly depending on the judge and county, but the base calculation is consistent across the state.