Source: Justia — Child Support Laws and Forms: 50-State Survey (verified 2024). Map shows the calculation model each state uses to determine child support obligations. The formula determines how much the non-custodial parent pays and whether the custodial parent's income is considered.
What This Means for the Non-Custodial Parent
Income Shares (41 states — blue): Both parents' incomes are combined to estimate the child's needs in an intact household. The obligation is split proportionally by income share. If you earn 70% of combined income, you pay 70% of the base obligation. Critically, the custodial parent's income directly reduces your payment — but courts can impute income if they believe a parent is voluntarily underemployed.
Flat Percentage of Income (4 states — red): Alaska, Mississippi, Nevada, and Wisconsin apply a fixed percentage of only the non-custodial parent's income. The custodial parent's income is completely irrelevant. Rates typically range from 17–20% for one child up to 33–41% for five or more children.
Varying Percentage of Income (3 states — orange): North Dakota, Texas, and DC use a percentage that scales with income bracket. Texas applies 20% for one child, 25% for two, up to 40% for five or more — applied to net monthly resources (cap raised to $11,700/month effective September 1, 2025, up from $9,200).
Melson Formula (3 states — purple): Delaware, Hawaii, and Montana use the most complex model. Courts first reserve a self-support allowance for each parent's basic needs, calculate the child's base support need, then add a standard-of-living adjustment. In practice this often yields higher orders than Income Shares because the formula explicitly factors in each parent's lifestyle.
Critical warning for all 50 states: Child support does NOT automatically decrease if you lose your job. You must petition the court for a modification. Non-payment results in license suspension, wage garnishment, passport denial, and potential incarceration. Courts can also impute income — assigning you earning capacity even if you are currently unemployed.
Income Shares (41 states) considers both parents' incomes — the custodial parent's earnings reduce your obligation. Flat Percentage states (AK, MS, NV, WI) ignore custodial income entirely. DC uses Varying % but adjusts for custodial income. Source: Justia 50-State Survey, verified 2024.