Montana Child Support Calculator & Guide (2025)

Overview of Montana Child Support

Montana uses the Income Shares Model under Montana Code Annotated §40-5-209. This model estimates the amount of money parents would spend on their children if the family were intact, then divides that obligation between the parents proportionally based on their incomes.

This approach ensures that children receive the same proportion of parental income they would have enjoyed had the parents remained together. Montana's Child Support Enforcement Division, part of the Department of Public Health and Human Services, administers and enforces child support orders statewide.

How Child Support Is Calculated in Montana

The Montana child support formula works as follows:

1. Determine each parent's gross income: Include wages, salaries, bonuses, self-employment income, investment income, and other sources
2. Combine both parents' incomes to find the total household income
3. Consult the Montana support schedule to find the base support obligation for the combined income level and number of children
4. Add health insurance and childcare costs to the base obligation
5. Allocate each parent's share proportionally based on their percentage of the combined income
6. Apply the self-support reserve to ensure the paying parent retains at least $1,038/month

Montana Income Shares Example

Key Factors in Montana Calculations

Gross Income Definition

Montana considers gross income from all sources, including:

• Wages, salaries, and commissions
• Bonuses and overtime
• Self-employment income
• Rental income and investment returns
• Social Security benefits and pensions
• Workers' compensation and unemployment benefits

Imputed Income

Montana considers imputed income for underemployed parents. If a parent is voluntarily unemployed or underemployed, the court may assign an earning capacity based on the parent's work history, education, skills, and the local job market.

Extraordinary Medical Expenses

Extraordinary medical and dental expenses that exceed typical costs are shared proportionally between both parents based on their income shares.

Minimum and Maximum Amounts

Self-support reserve: Montana protects low-income obligors with a self-support reserve of $1,038 per month (2024). The paying parent must retain at least this amount for their own basic needs.

Low-income adjustments: For parents with income near the poverty level, Montana provides reduced obligations to ensure the parent can still meet their own basic living expenses.

Modification and Enforcement

Modification

Montana allows modification of child support orders when:

• There has been a material and substantial change in circumstances
• A significant change in either parent's income occurs
• Custody arrangements change substantially
• The child's needs change significantly

Enforcement

The Montana Child Support Enforcement Division enforces orders through:

• Income withholding from paychecks
• Tax refund interception (federal and state)
• Driver's license suspension for non-payment
• Professional license suspension
• Credit bureau reporting of delinquencies
• Contempt of court proceedings
• Liens on property and financial accounts
• Passport denial for arrears exceeding $2,500

Get your Montana estimate: Use our free child support calculator to see what you might owe or receive under Montana guidelines.