Child Support Calculator

How the Income Shares Model Works

The income shares model (used by about 40 US states) starts from the principle that children should receive the same proportion of parental income they would have received if the parents lived together. The calculator combines both parents' incomes, applies a state-derived percentage based on number of children (17% for one, 25% for two, 29% for three, 31% for four, 33% for five), and calculates the total annual support obligation for the children. Each parent then pays their proportional share — so if the payor earns 67% of combined income, they pay 67% of the obligation.

The Three Main Models

Income Shares is the most common (40 states). It's the model this calculator uses. Percentage of Obligor Income (used by about 6 states including Texas and Mississippi) takes a flat percentage of the non-custodial parent's income only — typically 20% for one child, 25% for two, 30% for three. Melson Formula (Delaware, Hawaii, Montana) is a hybrid that ensures both parents retain a minimum self-support reserve before calculating the obligation. Each model produces different results for the same family, sometimes by hundreds of dollars per month.

What's Not in the Base Calculation

Base child support covers the basics — food, shelter, clothing, transportation. Most state guidelines add separate line items for: health insurance premiums (split proportionally), uninsured medical expenses (deductibles, copays, out-of-pocket), work-related childcare costs, mandatory school fees, and sometimes private school or extracurricular activities. These add-ons can increase the actual order by 30–60% beyond the calculator's estimate. If you want a complete picture, ask a family law attorney to run the full state worksheet.

Custody Time Affects Child Support

Most states adjust child support based on parenting time. If the non-custodial parent has the children more than ~30% of overnights, support typically reduces (sometimes called a "shared parenting adjustment"). At true 50/50 custody, support often becomes purely a function of income disparity rather than parenting time. The calculator doesn't account for custody schedule, so its estimate is closest to a primary-custody arrangement (one parent has the children most nights). For shared parenting, expect the actual amount to be lower.

Frequently Asked Questions

Can we agree to no child support?

Most states require minimum support regardless of parental agreement, especially if either parent receives public assistance.

Does child support count as income for taxes?

No — child support is neither taxable to the recipient nor deductible to the payor at the federal level.

What happens if I can't pay?

File for modification immediately. Don't fall behind — back payments accrue interest and can lead to wage garnishment.

Does remarriage affect child support?

Generally no — a new spouse's income doesn't directly count, though it may be considered indirectly.

How do I enforce a child support order?

Through your state's child support enforcement office. Wage garnishment is the most common enforcement tool.