How Montana calculates child support
Montana uses the Melson Formula — a more detailed version of the income shares model used only by Delaware, Hawaii, and Montana. The Melson Formula prioritizes ensuring both parents can meet their own basic needs before calculating how much support the children receive.
How the Melson Formula works
First, each parent is entitled to keep a self-support reserve — enough income to cover their own basic living needs. Only income above that reserve is available for child support calculations. Next, a primary support need per child is established. Both parents contribute to that minimum proportionally. Any remaining income above the primary need is then shared with the children through a Standard of Living Adjustment (SOLA).
Important note
The Melson Formula is significantly more complex than other models. The estimate shown above is a simplified approximation. For accurate results in Montana, use Montana's official child support worksheet or consult a family law attorney.