How Child Support Is Calculated in Michigan

The formula is the starting point

MCL 552.605(2) requires the court to order child support in the amount determined by the Michigan Child Support Formula (MCSF)developed by the State Friend of the Court Bureau. The formula is the MCSF manual plus its most current supplement (2025 MCSF 1.01(A)). The 2025 manual took effect January 1, 2025; the MCSF page lists the current materials.

A child support obligation covers three parts (2025 MCSF 3.01(A)):

• base support, adjusted for parenting time;
• medical support, including ordinary and additional medical expenses, health care coverage, and premiums; and
• child care expenses.

How the calculation works

1. Each parent’s net income. Income is broad: wages, overtime, commissions, bonuses, business and rental earnings, and many benefits (2025 MCSF 2.01(C)). “Net income” is income minus the deductions the manual allows, and it is not the same as take-home pay (2025 MCSF 2.01(A)).
2. Each parent’s share. Obligations are generally apportioned by each parent’s percentage share of combined net income (2025 MCSF 3.01(B)).
3. Base support, from the combined net family income and the General Care Support Table in the supplement, using the total number of children the parents have in common (2025 MCSF 3.02).
4. The parental time offset. Base support is adjusted by an equation that uses each parent’s approximate annual overnights (2025 MCSF 3.03). Without credible evidence that practice has changed, the number of overnights used in the last order is presumed to continue (2025 MCSF 3.03(C)(2)).
5. Medical and child care obligations are added (2025 MCSF 3.04 to 3.06).

For a rough figure from these steps, try the child support estimator with Michigan selected.

Imputed (potential) income

If a parent is voluntarily unemployed or underemployed, or has an unexercised ability to earn, income can include the potential income that parent could earn, subject to the parent’s actual ability (2025 MCSF 2.01(G)). The manual lists factors to weigh, including work history, education and skills, health, availability of work and prevailing wages in the area, diligence in looking for work, and the presence of the children in that parent’s home.

Imputed income generally should not be based on more than a 40-hour week or include potential overtime (2025 MCSF 2.01(G)(1)(a)). The manual also says imputation cannot rest on generalized assumptions, such as full-time minimum wage, instead of the parent’s actual ability and likelihood of earning (2025 MCSF 2.01(G)(4)).

In a Friend of the Court support review, the office may impute income to a party who fails or refuses to provide requested information, and a recommendation based on imputed income must state the factual assumptions behind it (MCL 552.517b(6)).

Deviating from the formula

The court may deviate if applying the formula would be unjust or inappropriate, but it must state, in writing or on the record, the formula amount, how the order deviates, the value of any property awarded instead of support, and why the formula would be unjust or inappropriate (MCL 552.605(2)). Parents can agree to a deviation, but the same findings are still required (MCL 552.605(3)). The 2025 MCSF 1.04(E) lists situations that may justify a deviation, such as a child’s special needs or extraordinary educational expenses, and notes that a deviation factor does not require the court to deviate.

Changing an existing order

There are two routes.

• Friend of the Court review. In an FOC case, either party can ask in writing for a review. The office does not have to act on more than one request from a party every 36 months (MCL 552.517(1)(b)). After the review, the FOC sends a recommended amount, and either party has 21 days from the mailing of that notice to object (MCL 552.517b(3)). If no one objects, an order is prepared for the court. A review adjustment does not require proof of a substantial change in circumstances (MCL 552.517b(7)).
• Motion. File FOC 50, Motion Regarding Support (Rev. 6/19). The court may only modify support on a motion if it finds a substantial change in circumstances (MCL 552.517b(8)). The other party can respond on FOC 51.

After a review, the FOC must petition to modify only if the difference exceeds the minimum threshold for modification: 10 percent of the current support payment or $50 per month, whichever is greater (2025 MCSF 4.05; MCL 552.517(5)(a)).

How long support lasts

Support is generally ordered until a child turns 18 (MCL 722.27(1)(a)). Under MCL 552.605b, the court may order support while the child regularly attends high school full time with a reasonable expectation of graduating, living full time with the recipient or at an institution, but never past 19 years and 6 months of age.

The order itself

Support provisions must be on the latest SCAO Uniform Support Order (MCR 3.211(D)), currently FOC 10/52, Uniform Child Support Order (Rev. 11/25). Support orders do not accrue interest (MCL 552.603(11)).

Primary sources

Rules and forms change. Check the current version at the source before you file.

• 2025 Michigan Child Support Formula Manual (SCAO)
• MCL 552.605, use of the formula and deviations
• MCL 552.605b, support after 18
• MCL 552.517, support review
• MCL 552.517b, review procedure and modification
• MCL 552.603, no retroactive modification
• MCL 722.27, support until 18
• MCR 3.211(D), Uniform Support Orders