Child support calculator

Estimates only. Child support is calculated using your state's specific guidelines and actual income verification. This calculator provides a general estimate. Your attorney or the court calculates the exact amount using your state's formula. See our full disclaimer.

Child support estimator

Your gross monthly income ($) Before taxes. Include wages, self-employment, bonuses (averaged), and other regular income.

Other parent's gross monthly income ($)

Number of children needing support

Physical custody arrangement

Monthly health insurance cost for children ($) Only the incremental cost to add children to the plan (not the entire premium).

Monthly childcare/daycare cost ($) Work-related childcare is typically added to the basic support obligation.

Your state's calculation model

Your child support estimate

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A family law attorney calculates the precise amount using your state's formula, addresses deviation requests, and ensures the order includes healthcare, childcare, and extracurricular costs. Free consultation.

How do states calculate child support?

All 50 states use income-based child support formulas mandated by federal law, though the specific calculations differ. The most widely used model is the income shares model (38 states), which starts with the combined gross income of both parents, looks up the basic child support obligation on a state schedule, and then allocates it proportionally between parents based on their share of combined income. The parent who does not have primary physical custody pays their proportional share to the primary custodial parent.

The percentage of income model (used in Texas, Wisconsin, New York, and a few others) calculates support based solely on the paying parent's income using a fixed percentage - for example, Texas uses 20% of net income for one child, 25% for two, 30% for three, and so on. Both models produce broadly similar results at similar income levels. Additional costs like health insurance premiums for the children and work-related childcare are typically added to the base support obligation and shared proportionally. If custody is a key dispute, use the custody agreement builder alongside this calculator since custody arrangement significantly affects the support calculation.

What does "imputed income" mean for child support?

If a parent is voluntarily underemployed (working below their potential) or unemployed without good reason, courts can "impute" income to them - calculating support based on what they could earn rather than what they actually earn. This prevents parents from reducing their support obligation by quitting a job or taking a dramatically lower-paying position. Courts consider the parent's work history, education, skills, and local job market. If your co-parent has voluntarily reduced their income, your attorney may request an imputed income calculation using the imputed income calculator.

When and how can child support be modified?

Child support can be modified when there's a substantial change in circumstances - typically defined as a change that would result in at least a 15% to 20% change in the support amount, depending on state. Common grounds include significant income increase or decrease, change in custody arrangement, change in the child's needs, or a parent's new child support obligation for another child. Modifications are not automatic - you must file with the court and get a new order. Paying less than the ordered amount without a court modification order results in arrears with interest, even if both parties informally agree to the change.

Frequently asked questions about child support

Parents cannot waive child support by private agreement - child support belongs to the child, not the parent, and a parent cannot waive the child's rights. Courts can approve a below-guideline amount if both parents agree and the court finds it serves the child's best interests, but this requires a court order. Informal agreements to pay less than the court-ordered amount are unenforceable and result in mounting arrears with interest, even if the receiving parent verbally agreed. Any change to the support amount requires a formal court modification.

Non-payment of child support (arrears) has serious consequences: wage garnishment (automatic income withholding from employer), bank account liens, tax refund interception, driver's license suspension, professional license suspension in many states, passport denial for arrears over $2,500, and ultimately contempt of court with possible jail time. Child support enforcement is handled by the state's Child Support Enforcement (CSE) agency at no cost to the receiving parent - you don't need an attorney to begin enforcement. Interest on unpaid arrears accrues automatically at state-set rates, typically 6% to 12% annually.

Standard child support orders terminate when the child reaches the age of majority (18 in most states, or upon high school graduation up to 19). College expenses are separate from child support. A few states (notably New York, New Jersey, and Massachusetts) allow courts to order post-secondary educational support. Many separation agreements include college expense provisions negotiated at divorce. If college funding is a concern, address it explicitly in your separation agreement rather than assuming the court will order it later - most won't.

In most states, a new spouse's or partner's income does not directly affect child support calculations - child support is based on the biological or adoptive parents' incomes, not their household partners'. However, remarriage can indirectly affect support in limited ways: if a new spouse's income reduces the paying parent's living expenses, courts may view the paying parent as having greater ability to pay; and if the receiving parent remarries and their new spouse provides significant financial support, courts in some states allow this as a factor in modification requests. The impact varies significantly by state.

The IRS tiebreaker rule gives the dependency exemption to the parent who has primary physical custody (more overnight visits) unless both parents agree otherwise in writing using Form 8332. Many divorce agreements alternate the dependency exemption annually or assign it to the higher-earning parent who benefits more from it. The child tax credit, earned income credit, and childcare credit can add $2,000 to $8,000+ in annual tax savings - making the tax exemption decision a meaningful financial negotiating point in divorce proceedings. An accountant or financial advisor should model the tax benefit for each spouse.