Calculate Child Support
Before taxes. Include wages, self-employment, bonuses.
Montana uses the Melson Formula — both incomes required.
0 = no custody · 91 = 25% · 182 = 50/50 · 365 = full custody
$0
estimated monthly support payment
⚠️ Estimate only. Actual court-ordered amounts may vary. Verify with a licensed Montana family law attorney.
ℹ️ Montana uses the Melson Formula — Montana uses the Melson Formula. Considers each parent's self-support reserve before calculating child support.
How Child Support Works in Montana
Montana uses the Melson Formula to determine child support obligations.
The Melson Formula first reserves a self-support amount for each parent's basic needs, then calculates the child's primary support needs, and finally adds a standard of living adjustment. Only 3 states use this model.
How Montana Compares to Other States
See how Montana's child support rules compare to other states.
| State | Formula | Support Ends | Arrears Rate | Mod. Threshold |
|---|---|---|---|---|
| ★ Montana (you) | Melson Formula | 18 | 10% | 10% |
| Delaware | Melson Formula | 18 | 5% | 10% |
| Idaho | Percentage of Income | 18 | 5% | 15% |
| Michigan | Income Shares | 18 | 5% | 10% |
| Ohio | Income Shares | 18 | 5% | 10% |
| Alaska | Percentage of Income | 18 | 6% | 15% |
| Florida | Income Shares | 18 | 6% | 15% |
| Louisiana | Income Shares | 18 | 6% | 25% |
| New Hampshire | Income Shares | 18 | 6% | 15% |
Showing 8 comparison states. View all 50 states →
Frequently Asked Questions
How is child support calculated in Montana?
Montana uses the Melson Formula model. Montana uses the Melson Formula. Considers each parent's self-support reserve before calculating child support.
When does child support end in Montana?
Child support generally ends when the child turns 18 in Montana.
Can I modify child support in Montana?
Yes. Montana requires a 10% or greater change in income to qualify. Use our modification checker →
Does 50/50 custody eliminate child support in Montana?
Not automatically. The higher-earning parent typically still pays support with 50/50 custody. See our 50/50 guide →
What income is used for child support in Montana?
Income includes wages, self-employment, bonuses, rental income, unemployment benefits, disability payments, and Social Security. Courts may impute income if a parent is voluntarily underemployed.