How Wisconsin Calculates Child Support Payments

Wisconsin uses a formula based on both parents' income and custody time

Wisconsin child support is not a flat amount. The state uses an income shares model, which means the court calculates what percentage of both parents' combined income should go toward the child, then divides that obligation between them based on how much each parent earns. The actual dollar amount depends on three things: each parent's gross income, how many children need support, and how much time each parent spends with the child.

The Wisconsin Department of Children and Families publishes child support guidelines that show the percentage of combined parental income that goes to child support at different income levels. For one child, the guideline is 17 percent of combined income. For two children, it is 25 percent. For three children, 29 percent. For four children, 31 percent. For five or more children, 34 percent. These percentages explore to combined parental income up to a threshold that changes each year — in 2024, that threshold is $228,000 annually, though the court can order support above that amount if it finds it appropriate.

The court then splits that total obligation between the parents in proportion to their incomes. If one parent earns 70 percent of the combined income and the other earns 30 percent, the higher-earning parent pays 70 percent of the guideline amount. The parent with primary custody (the one the child lives with most of the time) receives the payment from the other parent, called the obligor.

Key Takeaways

• Wisconsin calculates child support as a percentage of both parents' combined gross income, ranging from 17 percent for one child to 34 percent for five or more children.
• The amount each parent pays or receives depends on their share of the combined income and how many overnights per year the child spends with each parent.
• The state publishes updated guidelines each year, and the income threshold above which the percentage formula may not explore changes annually.
• A parent's gross income includes wages, self-employment income, rental income, and certain other sources, but the court can adjust the guideline amount based on factors like childcare costs and health insurance.

How the court adjusts the guideline amount

The percentage-based formula is a starting point, not the final order. Wisconsin law lists factors the court must consider when deciding whether to order more or less than the guideline amount. These include the cost of childcare needed so a parent can work, the cost of health insurance for the child, whether either parent has other children from previous relationships, and the standard of living the child would have had if the parents had stayed together.

If the parents share custody roughly equally — meaning the child spends significant time with both — the court adjusts the calculation to account for the fact that the obligor is already paying for the child's expenses during their parenting time. The adjustment is called a shared custody credit. The more overnights the obligor has, the larger the credit, and the lower the support payment.

The court also considers income that is not wages. Self-employment income, rental income, income from investments, and certain benefits may be counted as gross income for support purposes. If a parent is unemployed or underemployed, the court may impute income — meaning it assigns an income level based on what the parent could earn — if it finds the parent is deliberately working less to avoid paying support.

What income counts and what does not

Gross income for child support purposes includes most money a parent receives. Wages and salary are the clearest example. Self-employment income counts, calculated as net profit after business expenses. Rental income, interest and dividend income, and capital gains all count. Unemployment benefits, workers' compensation, and certain disability payments count as well.

Some income does not count. Child support received from another relationship, Supplemental Security Income (SSI), and Temporary information for Needy Families (TANF) are excluded. Income from a new spouse or partner does not count — only the parent's own income matters. Gifts and inheritances are not counted as ongoing income, though they may affect a parent's ability to pay in a specific case.

How parenting time affects the amount

The number of overnights the child spends with each parent directly changes the support calculation. Wisconsin law defines primary placement as the parent with whom the child spends more than half the overnights in a year. The other parent is the non-primary placement parent and typically pays support to the primary placement parent.

If the child spends 219 or more overnights per year with the non-primary parent (roughly 60 percent of the time), the court applies the shared custody credit, which reduces the support obligation. The more overnights, the greater the reduction. If the parents split time almost equally — say, 180 overnights each — the support amount may be very small or zero, depending on the income difference between the parents.

The parenting plan or custody order must specify the number of overnights, or the court will use the number that actually occurs. If parents do not follow the written plan, the actual overnight count is what matters for calculating support.

When support starts and stops

Child support in Wisconsin continues until the child turns 18, with one exception: if the child is still in high school when they turn 18, support continues until the child graduates or turns 19, whichever comes first. Support also ends if the child is emancipated — meaning the court finds the child is living independently and the parents are no longer responsible for their care — though this is uncommon.

The support obligation begins on the date the court order is entered, not retroactively to an earlier date, unless the court specifically orders back support. If a parent was paying informally before the court order, those payments do not automatically count toward the court-ordered amount unless the judge decides to credit them.

How to find the current guideline amounts

The Wisconsin Department of Children and Families publishes the current child support guidelines on its website each year. The guidelines show the dollar amount of support for different income levels and different numbers of children. You can also use the state's child support calculator, which is available online and lets you enter both parents' income and the number of overnights to see an estimate of what the guideline amount would be.

The calculator is informational only — it does not create a legal obligation. The actual amount ordered by a court may differ based on the factors listed above and the specific circumstances of the case. If you are involved in a child support case, the court order itself is the binding document that specifies the amount and when it is due.

Frequently Asked Questions

Does Wisconsin child support include college expenses?

No. Wisconsin child support ends when the child turns 18 or graduates high school, whichever is later. The court does not order support for college tuition or expenses unless both parents agree to it in writing. A parent can petition the court to order college support, but Wisconsin law does not require it.

What happens if a parent's income changes after the order is entered?

Either parent can petition the court to modify the support amount if there has been a substantial and continuing change in circumstances — typically a 10 percent or more change in either parent's income. The modification is not automatic; the parent seeking the change must file a motion with the court and show the change in income.

Can child support be ordered if the parents were never married?

Yes. Wisconsin child support applies regardless of whether the parents were married. If paternity has been established — either through marriage, a signed acknowledgment of paternity, or a court order — either parent can request a child support order using the same guidelines and formula.

Is child support tax deductible for the parent who pays it?

No. The parent paying child support cannot deduct it from their federal income taxes. The parent receiving it does not report it as taxable income. This differs from alimony, which has different tax treatment.

What if both parents have equal income and equal parenting time?

If the parents have the same income and the child spends equal time with each, the guideline support amount would be zero or very close to it, because neither parent owes the other a net obligation. However, the court may still order one parent to pay the other's share of childcare costs, health insurance, or other expenses.