Montana runs child support through ARM 37.62.101–.148 and the CS 404.2 tables, effective February 1, 2026, using a Melson-style annual worksheet. Each parent keeps a $20,748 personal allowance before the Primary Child Support Allowance is met pro-rata, then a standard-of-living adjustment is layered on, and a 12%-of-net minimum contribution floors each parent’s share regardless of the formula result. Montana’s calculation uses each parent’s actual taxes rather than an estimated deduction.
Key facts
| Model | Melson-style — ARM 37.62.101-.148, CS 404.2 tables (eff. 2026-02-01) |
|---|---|
| Personal allowance | $20,748/year per parent |
| Minimum contribution floor | 12% of net income |
| Tax treatment | Uses each parent’s actual taxes |
Official source: https://dphhs.mt.gov/cssd/services/Guidelines
Custody arrangements covered
- Melson-style personal-allowance-then-adjustment structure, floored at each parent’s 12%-of-net minimum contribution
Frequently asked questions
What rules govern Montana child support?
ARM 37.62.101–.148 and the CS 404.2 tables, effective February 1, 2026.
How much does each Montana parent keep before support is calculated?
A $20,748 annual personal allowance, before the Primary Child Support Allowance is met on a pro-rata basis.
Is there a minimum contribution in Montana?
Yes — each parent’s contribution is floored at 12% of their net income, regardless of what the formula would otherwise produce.
Does Montana use actual or estimated taxes?
Montana’s worksheet uses each parent’s actual taxes rather than an estimated flat deduction.
Update history
- — Montana went live using its Melson-style formula (effective 2026-02-01): each parent keeps a $20,748 personal allowance, the Primary Child Support Allowance is met pro-rata, then a standard-of-living adjustment applies, with a 12%-of-net minimum contribution floor.