Uses the income shares model. Results are estimates — courts apply state-specific guidelines. All calculations stay in your browser. · Updated 2026
Estimated Monthly Child Support Payment
Combined Parental Income
Basic Child Support Obligation
Paying Parent's Income Share
Custody Adjustment Applied
⚠️ Important: Child support formulas vary significantly by state. This calculator provides an estimate using the income shares model. Courts may deviate based on healthcare costs, childcare costs, extraordinary expenses, and other factors. Only a court order is legally binding. Consult a family law attorney for your state's specific guidelines.
Most US states use the income shares model for child support — it calculates a base obligation from both parents' combined income, then allocates it proportionally to each parent's share of that income. The paying parent typically pays 17–25% of their net income for one child, scaling up for additional children. States like Texas and New York use a simpler percentage-of-income model.
How Child Support Is Calculated
In income shares states, the process is: (1) Add both parents' gross (or net, depending on state) monthly incomes; (2) Look up the basic child support obligation for that combined income and number of children in state guidelines tables; (3) Calculate each parent's percentage share of combined income; (4) The paying parent's share of the basic obligation is their base child support payment; (5) Adjustments are made for health insurance costs, childcare, extraordinary medical expenses, and custody time (with significant custody time often reducing the payment).
What Can Modify a Child Support Order?
Child support orders can be modified when there is a "substantial change in circumstances" — typically a change in income of 15–20% or more, a change in custody arrangement, a change in the child's needs, or one parent becoming unemployed. Either parent can petition the court for modification. Many states have automatic review processes every few years. Note: private agreements between parents to pay less than the court order are not enforceable — only a new court order can change the obligation.
Frequently Asked Questions
The most common method is the income shares model (used in ~40 states): both parents' incomes are combined, a basic support obligation is determined from state guideline tables, and each parent contributes proportionally. The paying parent pays their share to the receiving parent. Texas and New York use a simpler percentage-of-income model: Texas pays 20% of net income for 1 child, 25% for 2, 30% for 3, etc. California uses an algebraic formula that accounts for custody time and net disposable income.
Not necessarily. With true 50/50 shared custody, child support is reduced significantly because both parents share physical custody costs directly. However, if there's a significant income disparity between parents, the higher-earning parent typically still pays some child support to equalize the children's standard of living between both households. The specific amount depends on your state's formula and the income difference between parents.
Child support typically ends when a child turns 18, or 19 if the child is still in high school. Some states extend support to age 21 or through college if ordered by the court. Support can end earlier if the child is legally emancipated (married, self-supporting, joins the military). Child support does not automatically end — you may need to formally request termination through the court when your child reaches the cutoff age, especially if payments are being withheld from your paycheck.
Non-payment of child support has serious consequences: wage garnishment (up to 50–65% of disposable income), bank account levies, tax refund interception, professional license suspension, driver's license suspension, passport denial, and contempt of court charges (including jail in serious cases). Child support enforcement agencies in every state actively pursue non-paying parents. Unpaid child support accrues as a judgment debt with interest in most states.
Yes, either parent can petition for modification when there is a "substantial change in circumstances." Most states define this as an income change of 15–20% or more, a custody change, job loss, disability, or a change in the child's needs. The modification is not retroactive — it only applies from the date of the new order, not from when circumstances changed. Don't simply stop paying — continue paying the existing order until a new court order is in place, or you'll owe arrears.