Montana Child Support Guidelines

Montana operates under the Melson Formula model, one of 3 U.S. states using this framework. For a parent supporting one child, the base guideline applies roughly 18% of income, scaling to 26% for two children and 32% for three. That places Montana at rank #18 of 51 states by single-child base percentage. Unlike capped states, there is no statutory income ceiling — the formula applies to the full reported income before deductions. Median household income across Montana is $60,560 annually, which shapes the real-world dollar obligations families face under these percentages.

On the enforcement side, the Montana child support program manages 36,000 active cases and collected approximately $80 million in the most recent OCSE reporting year. The state's collection rate of 63.4% compares to a national average of 60.6% across reporting states — placing Montana at rank #18 of 51 on collection efficiency, and rank #47 by caseload volume (national average: 285,686 cases per state). Paternity is established in 95.6% of Montana cases, compared to 94.9% nationally — a critical step because child support orders cannot be enforced without legal parentage on record. Orders are in place for 79.5% of the caseload.

Context matters when interpreting these numbers. A higher percentage-of-income figure does not automatically mean higher dollar obligations — the underlying income brackets, deductions, parenting-time adjustments, and self-support reserves vary meaningfully between states. Montana allows a parenting time adjustment, which can materially reduce the base obligation when the non-custodial parent exercises substantial overnight time. Use the official Montana calculator linked below for a binding estimate. Data sources: OCSE FY2022 Annual Report, Montana Revised Statutes, and Census ACS 2022.