How Is Child Support Calculated in Wisconsin — DCF 150 Explained

Two Formulas, One Threshold

Wisconsin calculates child support under DCF 150 of the Administrative Code, and which formula applies depends entirely on how much physical placement each parent has. The dividing line is 92 overnights per year — exactly 25% of the calendar.

Below 92 overnights for the non-primary parent: the percentage standard applies. At or above 92 overnights for each parent: the shared-placement formula applies.

This threshold creates one of the sharpest financial cliffs in Wisconsin family law. A placement schedule with 91 overnights uses a completely different calculation than one with 92 overnights — and the difference can be hundreds of dollars per month.

The Percentage Standard (Under 92 Overnights)

When one parent has primary placement (the other parent has fewer than 92 overnights), child support is a straight percentage of the paying parent's monthly gross income available for child support. The receiving parent's income doesn't factor in at all.

So if the paying parent has $5,000/month in gross income available for support and there's one child, the support obligation is $850/month. Straightforward — no adjustment for the other parent's income, no weighting for placement time.

The Shared-Placement Formula (92+ Overnights Each)

When both parents have at least 92 overnights, Wisconsin uses a more complex calculation that accounts for both parents' incomes and placement time. The logic: in shared placement, both parents are directly paying for the child's basic needs (food, housing, clothing) during their time, so the formula adjusts for that reality.

Here's how it works step by step:

1. Calculate each parent's gross income available for support
2. Multiply each income by the percentage standard for the number of children (17% for one child, etc.)
3. Multiply by 1.5 — the shared-placement multiplier that accounts for duplicated household costs (two bedrooms, two sets of clothing, etc.)
4. Multiply each result by the percentage of time the child spends with the other parent — this establishes each parent's liability
5. Subtract the lower liability from the higher — the parent with the higher number pays the difference

Worked example: One child. Parent A earns $6,000/month, Parent B earns $3,500/month. The placement schedule gives each parent about 182 or 183 overnights (50/50).

• Parent A's liability: $6,000 × 0.17 × 1.5 × 0.50 = $765
• Parent B's liability: $3,500 × 0.17 × 1.5 × 0.50 = $446.25
• Parent A pays Parent B: $765 − $446.25 = $318.75/month

Compare this to what Parent A would pay under the percentage standard if Parent B had primary placement: $6,000 × 0.17 = $1,020/month. That's a $701.25/month difference — which is why the 92-overnight threshold drives so many placement negotiations.

Equivalent Care for Non-Standard Schedules

Not every parent works a 9-to-5. Third-shift nurses, factory workers, and law enforcement officers may provide substantial daytime caregiving but can't accumulate traditional overnights.

DCF 150.02(10) addresses this with equivalent care: if a parent exercises a block of daytime placement of at least 6 consecutive hours and provides a meal during that block, it counts as a half-day (0.5 equivalent overnight). Two such blocks equal one overnight for support calculation purposes.

This expands the total day count beyond 365, recalculating the placement percentage based on the true caregiving picture. A parent who has 182 overnights plus two weekly 6-hour daytime blocks with meals gets credited with an additional 52 equivalent care days per year — shifting their placement percentage from 50% to roughly 56%.

One catch: you can't receive equivalent care credit for any daytime period that falls within 24 hours of an overnight you already claimed.

Beyond the Monthly Payment

The monthly support number isn't the full picture. The court must also address:

Health insurance. Under § 767.513, the court must assign responsibility for the child's health insurance. Under the DCF 150 guidelines, a parent is required to carry the child on an employer-provided plan only when the total premium cost is less than 10% of that parent's gross monthly income.

Out-of-pocket medical costs. Copays, deductibles, dental, orthodontic, and therapy expenses not covered by insurance are typically ordered split 50/50 between parents — separately from the monthly support amount.

Variable costs. Childcare, school tuition, special needs costs, and significant extracurricular expenses. In shared placement, the court allocates these in proportion to each parent's placement time, though income disparity can adjust the split.

Tax dependency. The court may alternate which parent claims the child for tax purposes, or split the exemption if there are multiple children. Typically, the claiming parent must be current on all support obligations for that tax year.

For a complete walkthrough of the DCF 150 formulas, worked examples for multiple scenarios, and how your placement schedule affects support, see the Wisconsin Custody & Parenting Plan Guide.

See more Wisconsin guides →