How Michigan Calculates Child Support
Michigan uses the Income Shares model for child support based on net monthly income. The Michigan Child Support Formula (MCSF) governs all child support proceedings in the state. It is developed and maintained by the Michigan Friend of the Court Bureau and updated every four years as required by federal law. Michigan's use of net income rather than gross income is its defining feature and must be calculated correctly before the rest of the formula produces an accurate result.
Net income in Michigan means income after subtracting federal income taxes, Michigan state income tax (a flat 4.25 percent in 2026), Social Security, Medicare, mandatory union dues, the parent's own health and dental insurance premiums, and mandatory employer-required pension contributions. Voluntary retirement contributions are not subtracted. Only contributions the employer requires as a condition of employment qualify.
The Michigan Child Support Formula
Michigan's calculation follows five steps.
Step one is calculating each parent's monthly net income. Step two is combining both net incomes to get the combined monthly net income. Step three is finding the base support amount in Michigan's support table using the combined net income and number of children. Step four is calculating each parent's income share and applying it to determine their individual obligation. Step five is applying the parenting time offset and adding healthcare and childcare costs.
A practical example: Parent A has a net monthly income of $3,500. Parent B has a net monthly income of $1,800. Combined net income is $5,300. Parent A's income share is 66 percent. If Michigan's table shows a base support amount of $1,100 for two children at $5,300 combined net income, Parent A's obligation before the parenting time offset is $726 per month.
Michigan also sets a minimum support amount, typically $25 per month, ensuring that even very low income paying parents maintain a formal obligation and a financial connection to their children's care.
Calculating Net Income in Michigan
Start with gross monthly income from all sources. Subtract federal income tax based on your filing status and actual withholding. Subtract Michigan state income tax at 4.25 percent flat. Subtract Social Security at 6.2 percent of wages up to $176,100 annually in 2026. Subtract Medicare at 1.45 percent of all wages. Subtract mandatory union dues if required by your employer. Subtract your own health and dental insurance premiums, not the children's portion, just the employee-only premium. Subtract any mandatory pension contributions required by your employer as a condition of employment.
The result is your Michigan net monthly income for child support purposes.
What Counts as Income in Michigan
Michigan courts include wages, salaries, commissions, bonuses, overtime, self-employment income, rental income, pension and retirement distributions, Social Security benefits, SSDI payments, workers' compensation, unemployment compensation, and income from any other regular source.
Courts can impute income to a parent who is voluntarily unemployed or underemployed based on employment history, skills, and the local job market. Michigan also considers in-kind compensation, employer-provided housing or a vehicle allowance, as income when those benefits meaningfully reduce a parent's living expenses.
Step-by-Step: How to Use This Calculator
Step 1. Calculate your net monthly income. Work through each deduction: federal tax, Michigan state tax at 4.25 percent, Social Security, Medicare, mandatory union dues, your own health and dental premiums, and required pension contributions. Do not enter gross income or take-home pay.
Step 2. Calculate the other parent's net monthly income using the same process.
Step 3. Enter the number of children covered by this order.
Step 4. Enter your parenting time percentage. Count actual overnights per year and divide by 365. Michigan applies a parenting time offset that scales from the first overnight.
Step 5. Add healthcare costs. Enter the monthly premium for the children's health insurance, not your own employee-only premium, which was already deducted in Step 1.
Step 6. Add childcare costs. Enter monthly work-related childcare expenses.
Step 7. Verify the net income figures in the results before accepting the final number. Net income errors are the most common source of inaccurate Michigan estimates.
Parenting Time Adjustments in Michigan
Michigan's parenting time offset is built into the MCSF and applies from the first overnight the paying parent has with the children. Unlike states that require a minimum threshold before any credit applies, Michigan begins reducing the obligation as soon as parenting time exists.
The offset grows as overnights increase. At 128 or more overnights per year, approximately 35 percent of the year, Michigan moves to a shared custody calculation. Both parents' obligations are calculated and offset against each other, with the higher earner paying the net difference.
Michigan caps the parenting time offset so it cannot reduce support below the $25 minimum floor. Even at equal parenting time with equal incomes, a minimum obligation may remain.
Add-On Expenses in Michigan
Michigan adds healthcare premiums for the children and work-related childcare costs to the base obligation, allocated proportionally by income share. Extraordinary medical expenses and other necessary costs may also be included in the court order.
Reading Your Results
The results show each parent's net monthly income, the combined net income, the base support amount from Michigan's table, the parenting time offset, add-on costs, and the final monthly obligation.
The most important check is the net income figure. Entering the wrong deductions, including voluntary 401(k) contributions or not deducting your own health insurance premium, will produce an inaccurate result.
After You Get Your Estimate
Michigan courts follow the MCSF in all standard cases. Deviation requires a written finding that the formula amount is unjust or inappropriate. Courts consider the child's needs, both parents' financial situations, and any special circumstances.
Modification in Michigan requires a change in circumstances. A 10 percent or more change in the support amount is the standard threshold. The MCSF is also reviewed on a four-year cycle, and either parent can request a review during that process.
Your local Michigan Friend of the Court office or a licensed Michigan family law attorney can help you verify your net income calculation and review your options.