Child Support in Michigan: The 2025 Michigan Child Support Formula Explained
Michigan family law · Last reviewed October 23, 2026
Michigan courts set child support with the Michigan Child Support Formula (MCSF), published by the State Court Administrative Office. The current edition took effect January 1, 2025. A court must follow it unless it finds the result "unjust or inappropriate" and explains why (MCL 552.605).
How the calculation works
- Net income. Each parent's income is figured under the formula's rules, then reduced to net income.
- Base support. The parents' combined net income and the number of children produce a base obligation, split between the parents by their shares of the combined income. (The 2025 edition dropped the old rule that kept each parent's share between 10 and 90 percent.)
- Parental time offset. The base obligation is adjusted for how many overnights each parent has.
- Add-ons. Health care coverage, ordinary and extraordinary medical costs, and child care are allocated between the parents.
The state's free MiChildSupport Calculator, from the Michigan Department of Health and Human Services, runs the formula. As MDHHS explains, "The calculations are based on the Michigan Child Support Formula Manual," and the result "is only as accurate as the information that is entered." An estimate isn't an order.
Key figures in the 2025 formula
| Item | 2025 formula |
|---|---|
| Low Income Threshold | $1,255 a month of net income |
| Support at or below the threshold | 10 percent of that parent's income |
| Ordinary medical expenses included in support | $200 a year per child (it was $454 under the 2021 formula) |
| Top of the schedule | $17,871.57 of combined monthly net family income (not a cap) |
| Health insurance "reasonable cost" | Up to 6 percent of the providing parent's gross income |
| Child care | Presumed to continue to the last day of the month the child is under 13 |
| Change worth a modification | 10 percent of current support or $50 a month, whichever is greater |
Low incomes. "When a parent’s monthly net income does not exceed the Low Income Threshold, the parent’s base support obligation is 10 percent of that parent’s income." Above the threshold, a transition calculation phases in the regular formula.
High incomes. Above $17,871.57 of combined monthly net income, the formula continues with a base amount plus a percentage of the excess, "or at the court’s discretion." It isn't a ceiling on support.
Overnights: the parental time offset
The formula adjusts support for the time each parent spends with the children using an equation that raises each parent's overnights to the power of 2.5, so the adjustment grows quickly as time approaches equal. It applies "whenever the approximate annual number of overnights that each parent will likely provide care for the children-in-common can be determined." Equal overnights don't automatically mean zero support when the parents' incomes differ.
Health care, medical costs and child care
- Insurance. The formula looks for coverage at a reasonable cost: "a reasonable cost to a parent for providing health care coverage for the children does not exceed 6 percent of the providing parent’s gross income." Premiums for the children are shared by income.
- Ordinary medical. Support includes $200 per child per year for routine out-of-pocket costs; costs beyond that are split by income share.
- Child care. Work-related child care is shared by income, and the formula presumes the need continues "until the last day of the month the child is under the age of 13."
Spousal support and other income rules
Spousal support paid between the two parents in the case doesn't move income for child support purposes: "Alimony/spousal support paid between the parents in the case under consideration is not included as its recipient’s income but remains its payer’s income."
Deviations
A court may depart from the formula only if applying it "would be unjust or inappropriate," and it must state in writing or on the record the formula amount, the amount ordered, how it departs, and why (MCL 552.605(2)). Parents can agree to a different amount, but the court must still make those findings. The formula manual lists the recognized reasons, from a child's special needs to a parent's child care share exceeding half of base support.
How long support lasts
Support ordinarily runs until the child turns 18 (MCL 552.17a). The court can order it to continue while the child regularly attends high school full time with a reasonable expectation of completing enough credits to graduate, and lives full time with the parent receiving support or at an institution, "but in no case after the child reaches 19 years and 6 months of age" (MCL 552.605b). Michigan law doesn't require parents to pay for college.
Who runs the system
The Friend of the Court office in each county handles support orders: it investigates, recommends, enforces and reviews them, and payments go through the Michigan State Disbursement Unit. The MDHHS Office of Child Support helps locate parents and opens cases; county prosecutors establish paternity and support in some cases.
Changing support
Either parent may ask the Friend of the Court or the court to review support. Under the formula's own threshold, a change is worth pursuing when a recalculation differs from current support by 10 percent or $50 a month, whichever is greater. (One Friend of the Court Bureau brochure says "whichever is less"; the formula manual, which governs, says "whichever is greater.")
When the formula changes
The 2025 edition is current. SCAO publishes new supplements "when required by changes in important economic data or the child support laws," and the formula is reviewed periodically; no date for the next edition has been announced.
Frequently asked questions
How is child support calculated in Michigan?
With the Michigan Child Support Formula: the parents' net incomes and number of children set a base amount, split by income share and adjusted for overnights, health care and child care. The MiChildSupport calculator gives an estimate.
What is the minimum child support in Michigan?
There's no flat minimum. A parent with net income at or below the $1,255 monthly Low Income Threshold generally pays 10 percent of that income.
Does 50/50 custody mean no child support in Michigan?
No. The overnight offset reduces support as time becomes more equal, but when incomes differ, support usually remains.
When does child support end in Michigan?
At 18, or up to 19½ if the child is still attending high school full time with a reasonable expectation of graduating.
When did Michigan's new child support formula take effect?
The current formula took effect January 1, 2025. Among other changes, it set ordinary medical at $200 a year per child and the Low Income Threshold at $1,255 a month.
How much does income have to change to modify child support in Michigan?
Enough that recalculated support differs from the current amount by 10 percent or $50 a month, whichever is greater.