Estimate monthly child support using the Income Shares model — the formula used by most U.S. states. Enter both parents' incomes and custody arrangement for an instant estimate.
This calculator estimates the guideline amount — but the actual order is set by a judge and can deviate based on special circumstances. A family law attorney ensures the order accounts for all income sources, tax implications (child tax credits), and modification rights. Most offer free consultations.
Find a Family Law Attorney →Most states (37 of 50) use the Income Shares Model for calculating child support. This approach adds both parents' gross incomes together, looks up a "basic child support obligation" from a state-published schedule based on that combined income and the number of children, then divides that obligation proportionally between the parents based on their respective income contributions.
For example, if the paying parent earns $5,000/month and the receiving parent earns $2,500/month, the combined income is $7,500. If the basic obligation for 2 children at that income level is $1,500/month, the paying parent (who earns 67% of combined income) would owe approximately $1,000/month. Add-ons for health insurance premiums and work-related childcare are then typically split the same way.
Shared custody reduces the obligation. When the paying parent has significant parenting time (35–50%), most courts apply a reduction to the base amount because the paying parent is directly incurring costs during their parenting time. At true 50/50 shared custody, the "cross-obligation" method is applied — both parents calculate what they would owe the other, and only the difference changes hands.
Courts can deviate from the guidelines based on extraordinary medical expenses, special educational needs, a parent's significantly reduced earning capacity, or voluntary unemployment. Judges have discretion but must document their reasoning when deviating from the guideline amount.