Child Support Calculations in Wisconsin

Wisconsin uses a unique percentage-of-income model to calculate child support, governed by Wisconsin Administrative Code DCF 150. Unlike most states that use income shares, Wisconsin applies fixed percentages directly to the payer's income. Whether you're navigating an uncontested or contested divorce, understanding these calculations is essential for planning your financial future.

The Percentage-of-Income Model

Wisconsin's approach differs fundamentally from the income shares model used by most states. Rather than combining both parents' incomes and allocating shares, Wisconsin applies these standard percentages directly to the payer's monthly income available for child support (MIACS):

• 1 child: 17%
• 2 children: 25%
• 3 children: 29%
• 4 children: 31%
• 5+ children: 34%

These percentages are presumptive under DCF 150.035(2). For example, if the payer has monthly income available for child support of $4,000 and one child, the presumptive support is 17% × $4,000 = $680 per month.

Calculating Monthly Income Available for Child Support

Wisconsin uses a specific definition of income called Monthly Income Available for Child Support (MIACS) under DCF 150.03:

• Gross income: Wages, salaries, interest, dividends, Social Security disability/retirement benefits, unemployment, workers' compensation, undistributed business income, and military allowances
• Self-employment adjustments: Income modified for business expenses; courts may add wages paid to dependent household members and undistributed corporate income not necessary for business growth
• Imputed income: If voluntarily unemployed or underemployed without good cause, courts may impute earning capacity based on experience, skills, and job market
• Unknown income rule: When income cannot be determined despite due diligence, courts may impute 10-35 hours per week at minimum wage
• Asset imputation: Underproductive assets may have income imputed at the 6-month Treasury bill rate

Excluded from income: Child support received, foster/kinship care payments, most public assistance, and Supplemental Security Income (SSI). However, Social Security Disability Insurance (SSDI) is included.

Shared Placement: The 150% Multiplier

When each parent has at least 25% physical placement (92 or more overnights annually), Wisconsin uses a shared-placement formula with a unique 150% cost multiplier to reflect duplicated housing costs in two homes:

• Step 1: Calculate each parent's MIACS × basic percentage (17/25/29/31/34)
• Step 2: Multiply that result by 150%
• Step 3: Multiply by the proportion of time the child spends with the other parent
• Step 4: Offset the two amounts; the parent with the larger result pays the net difference
• Variable costs: Childcare, tuition, and special needs costs are allocated separately, typically proportional to placement time

Example: Parent A has MIACS of $2,000 with 60% placement; Parent B has MIACS of $3,000 with 40% placement; two children.

• A's calculation: $2,000 × 25% = $500 → × 150% = $750 → × 40% (B's time) = $300
• B's calculation: $3,000 × 25% = $750 → × 150% = $1,125 → × 60% (A's time) = $675
• Offset: $675 - $300 = $375 from B to A

Equivalent Care Credits

Wisconsin allows equivalent care credits that can push a parent over the 25% threshold. Under DCF 150.035(1)(ag), courts may credit daytime care blocks when the parent incurs substantially the same basic costs as an overnight. This can result in credited "overnights" exceeding 365 days annually.

For example, if a parent has 88 actual overnights but provides 20 days of full-time daytime care, the court may credit those 20 days, bringing the total to 108 credited overnights—qualifying for shared placement.

Split Placement Formula

When parents have two or more children and at least one child lives primarily with each parent, Wisconsin uses a split-placement formula under DCF 150.04(3):

• Calculate the per-child pro-rata rate (e.g., for 3 children: 29% ÷ 3 ≈ 9.67% per child)
• Each parent multiplies their MIACS by the sum of per-child rates for children placed with the other parent
• Offset the two amounts

Example: Three children total; Parent A has two; Parent B has one. A's MIACS is $2,800; B's MIACS is $3,800.

• Per-child rate: 29% ÷ 3 ≈ 9.67%
• A's obligation for B's one child: $2,800 × 9.67% ≈ $271
• B's obligation for A's two children: $3,800 × (2 × 9.67%) ≈ $735
• Offset: $464 from B to A

High-Income Payer Brackets

For payers with MIACS above $7,000 per month, Wisconsin applies reduced marginal percentages to upper income tiers under DCF 150.04(5):

• First $7,000: Standard percentages (17/25/29/31/34%)
• $7,000 to $12,500: Reduced rates—14% (1 child), 20% (2), 23% (3), 25% (4), 27% (5+)
• Above $12,500: Further reduced—10% (1 child), 15% (2), 17% (3), 19% (4), 20% (5+)

Example: MIACS of $14,000 with two children:

• First $7,000 @ 25% = $1,750
• Next $5,500 ($7,000-$12,500) @ 20% = $1,100
• Above $12,500 ($1,500) @ 15% = $225
• Total: $3,075 per month

Low-Income Payer Schedule

Wisconsin provides a reduced support schedule for payers with income between 75% and 150% of the federal poverty guidelines. For 2025, this means monthly MIACS between approximately $978 and $1,956 (based on one-person FPG).

• Appendix C: The low-income schedule provides specific dollar amounts (not percentages) based on income level and number of children
• Below 75% FPG: Courts may set an appropriate amount based on total economic circumstances, potentially below the table minimum
• Annual updates: The schedule is updated every March 1 with new federal poverty guidelines

Serial-Family Payer Adjustments

When a parent has multiple support obligations, Wisconsin uses a sequential subtraction method under DCF 150.04(1):

• List legal obligations in chronological order
• Calculate the first obligation amount
• Subtract that amount from MIACS to get "adjusted income"
• Calculate subsequent obligations using the adjusted income

Example: Parent has MIACS of $4,600 and pays $600/month for an earlier child. Adjusted MIACS for new case: $4,600 - $600 = $4,000. New case with two children: 25% × $4,000 = $1,000.

Estimate Your Wisconsin Child Support

Use our calculator below to estimate child support in Wisconsin. For official calculations, use the Wisconsin DCF calculators.

Medical Support and Add-Ons

Under DCF 150.05, courts must address children's health expenses:

• Reasonable cost: Health insurance is presumed reasonable if premiums don't exceed 10% of the insuring parent's MIACS
• Non-insuring parent contribution: May be ordered to contribute up to 10% of their MIACS toward premium costs
• Accessibility: Coverage must be accessible within 30 minutes or 30 miles of the child's residence
• Uninsured costs: Courts allocate uninsured medical expenses based on each parent's ability to pay
• Low-income protection: Parents below 150% FPG cannot be ordered to pay premiums unless at no cost

Deviations from the Standard

Courts may deviate from the presumptive amount under Wis. Stat. 767.511(1m) if the percentage standard would be unfair to the child or a party. The court must make on-record findings including:

• The guideline amount
• The amount of deviation
• Specific reasons why the guideline amount is unfair
• The basis for the modified amount

Deviation factors include: Child's and parents' financial resources, needs of other dependents, childcare costs, extraordinary travel expenses for visitation, child's special needs, educational needs, tax consequences, and earning capacity.

Duration of Support

Under Wis. Stat. 767.511(4):

• Standard termination: Age 18
• High school extension: Through age 19 if the child is pursuing a high school diploma or GED
• No college support: Wisconsin courts cannot order post-majority support for college, though parties may agree to it
• No disabled adult support: Unlike some states, Wisconsin has no statutory authority to order support for disabled adult children

Modification Standards

Under Wis. Stat. 767.59, modification requires a substantial change in circumstances. Presumptions of substantial change include:

• 33 months elapsed: Unless the order is expressed as a percentage of income
• Public assistance change: Either parent starts AFDC/W-2 participation
• Failure to disclose: Either party fails to provide required financial disclosure
• Material income change: Meaningful change in payer income (if not a percentage order)

Enforcement and Arrears Interest

Wisconsin provides robust enforcement through the Department of Children and Families:

• Interest on arrears: 0.5% per month (6% annually) simple interest under the current DCF pilot program
• Income withholding: Up to 50% of current support can be added to pay down arrears
• Tax intercepts: Federal intercept at $500+ owed to family; state at $150+
• License suspension: Driver's, professional, and recreational licenses when arrears equal 3 months' support or $1,000
• Passport denial: When arrears reach $2,500
• Lien docket: Liens attach to real and titled personal property
• Bank seizure: Available when lien reaches $1,000 or 3 months' support

Payment priority: Payments apply first to current support, then unpaid arrears, then interest.

Common Calculation Mistakes

• Forgetting the 150% multiplier: This is unique to Wisconsin shared placement and significantly increases obligations
• Wrong overnight threshold: Shared placement requires 92 overnights (25%), not a lower number
• Missing equivalent care credits: Daytime care blocks can count toward the 92-night threshold
• Ignoring high-income brackets: Above $7,000 MIACS, reduced percentages apply to upper tiers
• Using outdated low-income tables: Appendix C updates every March 1 with new FPG
• Confusing gross with MIACS: Wisconsin uses a specific income definition, not simple gross income

Key Takeaways

• Percentage-of-income model: 17/25/29/31/34% applied directly to payer's MIACS
• Shared placement (≥92 nights): 150% multiplier with cross-credit offset
• High-income brackets: Reduced percentages above $7,000 and $12,500/month
• Low-income schedule: Special rates for 75-150% FPG, updated annually
• Duration: To 18, or through 19 if in high school; no college support
• Modification: 33 months or substantial change in circumstances
• Arrears interest: 0.5%/month (6% annual) simple interest

For more information about Wisconsin divorce processes, see our Wisconsin divorce timeline and filing checklist. For property division information, review our Wisconsin marital property guide.