Child support in Michigan is calculated using the Michigan Child Support Formula, a statewide guideline that combines both parents’ net incomes, the number of overnights each parent has with the child, and shared costs for health insurance, uninsured medical expenses, and work-related childcare. The formula produces a specific monthly dollar amount, and every county uses it, so the result should be roughly the same whether the case is filed in Wayne County or Traverse City. The Friend of the Court office in each county and the assigned judge both run the same math.
The formula is required by statute. MCL 552.519 directs the State Court Administrative Office to develop and maintain it, and federal rules require Michigan to review its guidelines at least once every four years.1Michigan Legislature. Michigan Compiled Laws 552.519 – Friend of the Court Act The current version took effect January 1, 2025.2Michigan Courts. 2025 Michigan Child Support Formula Manual
What Goes Into the Formula
Four inputs drive the calculation:
- Each parent’s net income.
- The number of overnights the child spends with each parent per year.
- The cost of the child’s health insurance premium, plus any uninsured medical costs above an ordinary threshold.
- Work- or school-related childcare costs.
The formula first uses the two incomes to estimate what a family at that combined income level typically spends on a child. That produces a base support obligation. The overnight schedule then adjusts the base up or down, and the shared expenses are added on top in proportion to each parent’s income.
Figuring Each Parent’s Net Income
The starting point is gross income, and Michigan casts a wide net. It includes wages, salaries, commissions, bonuses, and tips, plus Social Security benefits, workers’ compensation, pension payments, and most other recurring sources of money.3Michigan Courts. 2025 Child Support Formula Manual – Determining Income The scope is deliberately broad because the formula is trying to capture what each parent actually has available.
Then come the deductions. Federal, state, and local income taxes are subtracted based on each parent’s actual filing status. Required retirement contributions and mandatory union dues come out. If a parent is already paying court-ordered support for children from another relationship, that amount is deducted too, so the same dollars aren’t counted twice. What’s left is net income, and that is the figure the formula runs through its tables.
When Income Gets Imputed
If a parent is voluntarily unemployed or working well below their earning capacity, the court can impute income, meaning the formula uses what the parent could reasonably earn rather than what they actually earn. The court looks at employment history, education, special skills, physical and mental health, the local job market, and how hard the parent has been looking for work.3Michigan Courts. 2025 Child Support Formula Manual – Determining Income Imputed income cannot exceed what the parent was previously earning, and it cannot assume more than a 40-hour week or include overtime or shift premiums.
A few boundaries on that rule. Incarceration generally does not count as voluntary unemployment. A parent who works full-time but stops picking up overtime or a second job is not considered underemployed either. The formula uses actual earnings from overtime and second jobs, but it won’t punish a parent for choosing not to work extra hours.
Disability Benefits
Social Security Disability Insurance counts as income because it replaces wages from prior employment. If a dependent child receives auxiliary SSDI benefits based on the paying parent’s work record, those payments may be credited toward the parent’s support obligation, potentially reducing or even satisfying the monthly amount owed. Supplemental Security Income is different. It cannot be garnished for child support because it is needs-based public assistance rather than replacement income.
How Overnights Change the Number
Michigan’s formula includes a parental time offset that reduces the base support obligation as the paying parent spends more overnights with the child.4Michigan Courts. 2025 Child Support Formula Manual – Calculating Each Parent’s Obligation The reasoning is direct: when a child stays overnight with a parent, that parent is feeding, sheltering, and otherwise directly spending on the child. Counting overnights prevents double-charging for costs already being covered.
The offset is applied through a mathematical adjustment, not a simple percentage. When parents share roughly equal parenting time, the support amount reaches its lowest point because both households absorb similar day-to-day costs. Even small changes to the overnight schedule can produce meaningful shifts in the monthly payment, which is why accurate overnight counts matter more than parents often realize at the outset.
Adding Healthcare and Childcare
Two categories of shared costs get layered on top of the base support figure, and both are split between the parents in proportion to their incomes.
For healthcare, the child’s health insurance premium is divided between the parents based on each parent’s share of combined net income. For routine out-of-pocket medical costs, the formula presumes families spend roughly $200 per year per child on ordinary medical expenses, and that amount is built into the base support calculation.5Michigan Courts. 2025 Michigan Child Support Formula Supplement When actual uninsured medical costs exceed the ordinary threshold, the extra is split between the parents based on their relative incomes. Courts can raise the ordinary expense amount if a child’s medical needs are consistently higher than typical.
Childcare is handled separately. Payments to licensed daycare providers, after-school programs, and similar arrangements incurred because of a parent’s work or school are divided between the parents and added to the monthly total. These costs reflect actual spending rather than a formula estimate.
Running the Numbers Yourself
Michigan offers an official online calculator called the MiChildSupport Calculator at pcal.state.mi.us. It runs the same formula the Friend of the Court uses. It is not a substitute for a court order, but it produces a realistic estimate before you walk into a courtroom. The output is only as good as the inputs, so be honest about income, overnights, and actual childcare and premium amounts if you want a number that will hold up.
When a Judge Departs From the Formula
The formula result is presumed correct, but MCL 552.605 lets a judge deviate when applying the formula would produce an unjust or inappropriate result.6Michigan Legislature. Michigan Compiled Laws 552.605 – Child Support Order; Deviation From Formula A judge who deviates has to state the formula amount on the record, explain how the order differs, and give specific reasons. The court has to document its reasoning; this is not a loose standard.
The MCSF manual identifies 18 situations where deviation may be warranted.7Michigan Courts. 2025 Michigan Child Support Formula Manual Common ones include a child with special needs or extraordinary educational expenses; extraordinary medical expenses affecting a parent or dependent; irregular bonus income that makes the standard calculation misleading; extraordinary jointly accumulated marital debt; a parent providing nearly all the support for stepchildren or other dependents whose own parents cannot contribute; and calculated amounts of $20 or less where enforcement costs outweigh the benefit. A catch-all lets the court weigh any other factor affecting the child’s best interests.
The existence of a deviation factor does not force a departure. It simply opens the door. Most cases stick with the formula result.
Two Things the Calculation Does Not Do
The formula answers what the monthly amount should be. It does not change how the payments are taxed, and it does not reach backward.
Child support payments are not tax-deductible for the parent who pays and are not taxable income for the parent who receives them.8Internal Revenue Service. Tax Information for Non-Custodial Parents That is a federal rule that applies regardless of how the Michigan order is structured.
And once a support payment comes due, it becomes a fixed debt under the federal Bradley Amendment. No court can retroactively forgive or reduce arrears, even if the paying parent later lost a job or became disabled. If circumstances change, the fix is to file for modification right away rather than let unpayable debt build up while the old number keeps running.