How Child Support Is Calculated
The three models and which states use them.
Reference only — no accounts, no personal data collected.Every U.S. state uses one of three basic structures to calculate child support. Knowing the model your state uses tells you what inputs matter and how the final number is built.
The Three Models
Income Shares
The most common model. Both parents' incomes are combined as if the child lived in an intact household, then the support obligation is split in proportion to each parent's share of that combined income.
Percentage of Income
A fixed percentage of the non-custodial parent's income, scaled by the number of children. It does not pool both parents' incomes the way Income Shares does.
Melson Formula
Used by only a few states. After setting aside a self-support reserve for each parent and a standard-of-living allowance for the children, the remaining income is shared proportionally between the parents and the children.
Which States Use Which Model
| Model | States |
|---|---|
| Income Shares | Alabama, Alaska, Arizona, Arkansas, California, Colorado, Connecticut, Florida, Georgia, Idaho, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Missouri, Nebraska, New Hampshire, New Jersey, New York, North Carolina, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, Tennessee, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, Wyoming |
| Percentage of Income | Mississippi, Nevada, New Mexico, North Dakota, South Dakota, Texas |
| Melson Formula | Delaware, Hawaii, Montana |
What This Means For You
Pick your state from the list below to see its specific model, the factors it weighs, and where to find the official support schedule. The guides are built from public state child-support guidelines and attorney-reviewed.
Frequently Asked Questions
What is the most common child-support model?
Income Shares is used by the large majority of states. It pools both parents' incomes and splits the obligation by each parent's share.
Which states use the Melson Formula?
Only a few states use the Melson Formula — Delaware, Hawaii, and Montana. It reserves a self-support amount for each parent first.
What is a percentage-of-income state?
In these states (such as Texas, Mississippi, Nevada, New Mexico, North Dakota, and South Dakota) support is a fixed percentage of the non-custodial parent's income per child.
Do all states update the schedule yearly?
No. Schedules change only when a state revises its guidelines, usually tied to cost-of-living or legislative updates rather than an annual refresh.