Montana Child Support Calculator (2026)
In Montana, the formula first makes sure each parent can cover their own basic living costs, then sets support for the children from both incomes, plus a share of any extra income. Use the free calculator below for an instant estimate.
Calculate Your Montana Child Support
Free estimate — official Montana guidelines
Include wages, salary, bonuses, and other income
How Much Is Child Support in Montana?
If you make $60,000 a year in Montana, child support for 1 child is estimated at $780 per month ($9,360 per year). Calculated after applying the self-support allowance and standard of living adjustment.
$1,000/week ($52,000/year): approximately $699/month for 1 child.
Montana Child Support Estimates by Income (2026)
| Annual Income | 1 Child | 2 Children | 3 Children |
|---|---|---|---|
| $40,000/yr | $606/mo | $1,038/mo | $1,405/mo |
| $50,000/yr | $680/mo | $1,135/mo | $1,522/mo |
| $60,000/yr | $780/mo | $1,278/mo | $1,702/mo |
| $70,000/yr | $887/mo | $1,435/mo | $1,902/mo |
| $80,000/yr | $997/mo | $1,599/mo | $2,112/mo |
| $100,000/yr | $1,223/mo | $1,935/mo | $2,543/mo |
| $120,000/yr | $1,452/mo | $2,278/mo | $2,983/mo |
Based on the Melson Formula with standard assumptions. Compare all states →
How Child Support Is Calculated in Montana
Factors That Affect Child Support in Montana
Both parents' gross monthly incomes
Number of children requiring support
Self-support allowance for each parent
Primary support need per child
Health insurance costs for the children
Work-related child care expenses
Standard of living adjustment on remaining income
Parenting time arrangement
Technical details and legal basis
Montana uses the Melson Formula model (MT Guidelines (Mont. Code Ann. § 40-4-204)) to calculate child support. This model first ensures each parent retains enough for basic needs (self-support allowance), then calculates the child's primary support need, and applies a standard of living adjustment.
Important Notes for Montana
- Montana uses the Melson Formula model, which first ensures each parent can meet their own basic needs before calculating child support.
- The Melson Formula calculates a primary support need for each child, then allocates costs between parents based on their share of combined income.
- A sliding standard of living adjustment (SOLA) is applied to remaining income: 14% for 1 child, 21% for 2, 27% for 3, 31% for 4, 35% for 5 children.
Example Calculation
Scenario: Parent A earns $5,000/month, Parent B earns $3,000/month, 2 children.
Step 1: Combined income: $8,000
Step 2: Parent A's share: $5,000 / $8,000 = 62.5%
Step 3: Look up basic obligation for $8,000 combined and 2 children.
Step 4: Multiply by Parent A's share (62.5%).
Adjustments for health insurance, child care, and parenting time may apply.
Key Facts: Child Support in Montana
- Montana uses the Melson Formula, which ensures each parent retains a personal allowance of $1,729 per month (2026) before calculating child support.
- The primary child support allowance is $519 per child per month under the 2026 Montana guidelines.
- A sliding standard of living adjustment (SOLA) is applied: 14% (1 child), 21% (2), 27% (3), 31% (4), 35% (5 children).
- Montana bases calculations on gross income from all sources.
- The Melson Formula provides a three-tier approach: parent self-support, child basic needs, and standard of living sharing.
Montana Child Support FAQ
How is child support calculated in Montana?
Montana uses the Melson Formula, a three-step model. First, each parent's personal allowance ($1,729/month for 2026) is subtracted from their gross income. Second, the primary child support allowance ($519/child/month for 2026) is allocated between parents based on their income shares. Third, a sliding standard of living adjustment (14%-35% depending on the number of children) is applied to any remaining income.
What is the Melson Formula used in Montana?
The Melson Formula is a child support calculation method that prioritizes three levels of need: the parent's self-support, the child's basic needs, and a standard of living adjustment. Montana adopted this approach to ensure parents can meet their own basic living expenses while still adequately supporting their children.
What income is used for Montana child support calculations?
Montana uses gross income from all sources, including wages, salaries, bonuses, commissions, self-employment income, rental income, and investment income. The court may impute income to a parent who is voluntarily unemployed or underemployed.
Can Montana child support be modified?
Yes, Montana child support orders can be modified if there is a significant change in circumstances, such as a substantial change in either parent's income, changes in the child's needs, or changes in parenting time. Either parent may request a review through the court or the Child Support Enforcement Division.
How long does child support last in Montana?
In Montana, child support generally continues until the child turns 18, or 19 if the child is still in high school. Support may continue beyond that for a child with a disability. Parents may also agree to support through college, but the court generally cannot order it beyond the age of majority.
Why is Montana's child support formula different from other states?
Montana is one of the few states that uses the Melson Formula instead of the income shares model most states follow. Income shares states start by splitting a shared support amount between the parents. Montana's Melson Formula first sets aside a personal allowance so each parent can cover their own basic needs, then funds the child's primary support need, and finally applies a standard of living adjustment to any remaining income.
Does the Montana child support calculator include alimony?
No, this calculator estimates child support only. Alimony, which Montana law calls maintenance, is a separate payment between spouses and is decided by the court under different rules. A judge may consider maintenance payments when reviewing each parent's finances, but it is not part of the child support formula on this page.
Is this Montana child support calculator accurate?
This calculator uses the official 2026 Montana guideline values: a $1,729 monthly personal allowance for each parent, a $519 per child primary support allowance, and a sliding standard of living adjustment from 14% to 35% based on the number of children. It gives a solid estimate, but it is not legal advice. A Montana court can adjust the final amount for things like health insurance, child care costs, and parenting time.
How much is child support for one child in Montana?
Montana has no single flat amount for one child, so the payment depends on both parents' incomes. For one child in 2026, the formula uses a $519 monthly primary support allowance plus a 14% standard of living adjustment on income left after each parent keeps a $1,729 personal allowance. Enter both incomes in the calculator above for an estimate based on your numbers.
Do I still pay child support with 50/50 custody in Montana?
You may still owe child support in Montana even with equal parenting time. The Melson Formula compares both parents' incomes, so when one parent earns more, that parent usually pays some support to the other. Parenting time is one of the factors in the guideline worksheet, and more time with the children can lower the amount.
Does Montana child support cover health insurance and child care costs?
Yes. The children's health insurance costs and work-related child care expenses are part of Montana's guideline calculation. A court can also adjust the final amount based on who pays for these items, so have those costs ready when you compare your estimate to a court order.
How do I pay or check my child support in Montana?
Child support payments in Montana are handled through the state's Child Support Enforcement Division. Contact the division to make a payment, check your balance, or get help enforcing an order. The official guideline rules behind this calculator are published by the Montana Judicial Branch at courts.mt.gov/child-support.
About This Calculator
Uses the official MT Guidelines (Mont. Code Ann. § 40-4-204) (2026 guidelines). Last verified: 2026-05-31.
Disclaimer: Estimates only, not legal advice. Actual amounts are set by Montana courts. Full disclaimer.
Methodology: Melson Formula model per MT Guidelines (Mont. Code Ann. § 40-4-204).