How Montana Calculates Child Support

Montana uses the Income Shares model to determine child support obligations. This page explains the guidelines, formula, and key factors.

Model Type

Income Shares

Income-shares model based on combined gross income and number of children per Montana ARM 37.62; each parent's obligation prorated by income share; adjusted for parenting days and add-ons (childcare, health insurance).

Income Basis & Definitions

Income Basis:

gross

Number Of Children On Order

Selects the base-support amount from the Montana guidelines schedule.

Source: ARM 37.62.106: Schedule of basic support

Parent A Income

Parent A gross income per guidelines definition.

Source: ARM 37.62.103: Income definition

Parent B Income

Parent B gross income per guidelines definition.

Source: ARM 37.62.103: Income definition

Parenting Time Handling

Custody Type Or Worksheet Selection

Calculator applies parenting days adjustment.

Source: ARM 37.62.124: Parenting days adjustment

Parenting Time Input

Number of parenting days per year with each parent.

Source: Parenting days input

Deductions & Adjustments

Other Child Support Or Dependents Adjustment

Adjustments for preexisting child support obligations.

Source: ARM 37.62.108: Other support obligations

Spousal Support Adjustment

Spousal maintenance adjustment.

Source: Spousal maintenance deduction

Add-Ons & Allocation

Work Related Childcare Costs

Childcare costs allocated between parents.

Source: ARM 37.62.118: Childcare costs

Child Health Insurance And Uninsured Medical

Health insurance and uninsured medical expense allocation.

Source: ARM 37.62.120: Medical support

Caps, Minimums & Deviations

Income Cap And Above Cap Handling

Schedule caps at combined income; above-cap at court discretion.

Source: Maximum schedule income

Deviation Factors And Findings

Deviation allowed; requires written findings per MCA § 40-4-204.

Source: MCA § 40-4-204: Deviation factors

Try the Calculator

Use our Montana child support calculator to estimate your obligation.

Official Sources

Montana Administrative Rules 37.62 (Child Support Guidelines)Montana Code Annotated § 40-4-204 (Child Support)