Montana Child Support Calculator
2026Estimate child support payments in Montana. Calculate expected MT child support obligations based on income, custody arrangement, and number of children using Montana guidelines.
Written and reviewed by Konstantin Iakovlev · Methodology · Updated
Total Annual Obligation
$37,600.00
Parent 1 Share
$27,072.00
Parent 2 Share
$12,032.00
Support Calculation
| Combined Gross Income | $100,000.00 |
| Base Obligation Rate (2 children) | 28% |
| Base Support Obligation | $28,000.00 |
| + Child Care Costs (annual) | $6,000.00 |
| + Health Insurance (annual) | $3,600.00 |
| Total Obligation | $37,600.00 |
Each Parent's Share
| Parent 1 Income Share | 60.0% |
| Parent 1 Annual Obligation | $27,072.00 |
| Parent 1 Monthly | $2,256.00 |
| Parent 2 Income Share | 40.0% |
| Parent 2 Annual Obligation | $12,032.00 |
| Parent 2 Monthly | $1,002.67 |
| Per Child (annual) | $18,800.00 |
Disclaimer: This calculator is for informational purposes only and does not constitute tax, financial, or legal advice. Results are estimates based on the information you provide and current rates. Always consult a qualified tax professional or financial advisor for advice specific to your situation.
How is child support calculated in Montana?
Montana applies the Melson formula (an Income Shares variant with a self-support reserve). The court first sets aside a self-support reserve to cover each parent's basic needs, then a primary support obligation is calculated from combined adjusted income, with any remaining income shared via a standard-of-living allowance.
The calculation typically adjusts for: (1) work-related childcare, (2) the child's portion of health-insurance premiums, (3) extraordinary medical expenses, and (4) parenting time when overnights cross a state-defined threshold (e.g., 20%–40% depending on jurisdiction). Pre-existing support orders for other children, alimony paid, and mandatory retirement contributions also reduce gross income before the formula applies.
Guideline figures are presumptive — judges may deviate upward or downward when applying them would be unjust given the child's needs, the parents' resources, or other relevant factors. Montana courts retain final discretion. Always confirm the current guideline tables and worksheet with the Montana child support agency or family court.
Montana child support: model, official calculator, enforcement agency
- Guidelines model
- Melson Formula
- Official calculator
- Montana Child Support Guidelines (ARM 37.62)
Montana is one of just three states using the Melson Formula (with Delaware and Hawaii). The model first calculates each parent's self-support reserve, then primary support, then a "standard of living adjustment" for excess income. Montana's Child Support Enforcement Division within the Department of Public Health and Human Services administers approximately 22,000 cases — among the smallest case loads in the country. Payments process through the Montana State Disbursement Unit.
Montana Key Rates & Limits (2026)
| State Income Tax | progressive (up to 5.7%) |
| State Sales Tax | 0% |
| Minimum Wage | $10.85/hr |
Montana child support — frequently asked questions
How is child support calculated?
Most states use the income shares model, which estimates what parents would have spent on the child if they lived together, then divides that based on each parent's income share. Factors include gross income, number of children, custody arrangement, and healthcare/childcare costs.
Can child support be modified?
Yes. Either parent can request a modification if there is a substantial change in circumstances, such as a significant income change (increase or decrease), job loss, change in custody arrangement, or changes in the child's needs.
At what age does child support end?
In most states, child support ends at age 18 or high school graduation (whichever comes later). Some states extend support to age 19-21 or through college. Court orders may specify different end dates based on individual circumstances.