Montana Child Support Calculator 2026
Montana uses the Melson formula, which this page does not reproduce. Enter both parents' incomes to see each parent's share of combined income, then use the official Montana source linked below for the guideline amount. Calculated privately in your browser.
Estimate only — the court or the child support agency sets the order. Official source: Montana child support guidelines, tables and worksheets.
Montana is one of three states that use the Melson formula for child support. Each parent first keeps a self-support amount, the children's basic needs are then shared from the income that is left, and a further percentage of remaining income is added. This page shows each parent's share of combined income only; the guideline amount comes from the official Montana source.
How Montana Child Support Is Calculated
The National Conference of State Legislatures classes Montana, with two other states, as a Melson formula state. The formula is a more detailed version of income shares that protects each parent's own basic needs before support is set. Its allowances and percentages are published by the state and change when the guidelines are reviewed, so this page does not embed them.
The Montana worksheet defines which income counts and which deductions are allowed, so enter the figure it asks for rather than take-home pay.
| Step | On this page? |
|---|---|
| Each parent's share of combined income | Yes — simple arithmetic, shown for orientation |
| Self-support allowance for each parent | No — set by the Montana guidelines |
| Children's primary support need | No — set by the Montana guidelines |
| Standard-of-living adjustment | No — set by the Montana guidelines |
| Insurance, childcare and parenting time | No — handled on the official worksheet |
Worked Example: Montana Income Shares
With the default figures, the paying parent has $5,000 a month and the other parent $3,000. Combined income is $8,000, so the paying parent's share is 62.5% and the other parent's is 37.5%. To finish the calculation you would look up $8,000 of combined income and 2 children in the Montana guidelines and apply those shares.
Insurance, Childcare and Parenting Time in Montana
Montana adds the children's health insurance and childcare, and adjusts for parenting time, inside its own worksheet. Because the Melson formula divides support by the income each parent has left after the self-support amount, this page does not estimate those figures.
Any adjustment for parenting time (overnights) is made on the state worksheet or by the court and is not estimated here.
Estimate Only: Who Sets the Montana Order
This page gives an estimate only — the court or the state child support agency sets the order, and either can depart from the guideline where the law allows. Before relying on any figure, check the amount against the Montana child support guidelines, tables and worksheets.
If your income, the parenting schedule or the children's needs change, ask the court or the agency to review the order, and keep paying the ordered amount until it is changed. Last updated: October 2026.
Frequently Asked Questions
How is child support calculated in Montana?
Montana uses the Melson formula. Each parent first keeps a self-support amount, the children's basic needs are then shared from the income that is left, and a percentage of any remaining income is added as a standard-of-living adjustment. A court or the state child support agency sets the final amount.
Does this calculator give the Montana guideline amount?
No. It shows each parent's share of combined income. Montana uses the Melson formula, which sets aside a self-support amount for each parent first, so the official split and the support amount can differ. Use the official Montana source linked on the page.
What income does Montana use for child support?
The Montana worksheet defines which income counts and which deductions are allowed. Enter the monthly figure the official worksheet asks for, for both parents, rather than take-home pay.
How are health insurance and childcare handled in Montana?
Montana adds the children's health insurance and childcare, and adjusts for parenting time, inside its own worksheet. Because the Melson formula divides support by the income each parent has left after the self-support amount, this page does not estimate those figures.
Who decides the final child support amount in Montana?
A court or the state child support agency sets the order. Guideline figures are a starting point, and the decision-maker can depart from them where the law allows. An online estimate, including this one, is not an order.