Child Support Estimator
Pick your state, enter both parents' monthly incomes and the number of children, and see a realistic monthly range under your state's formula, with the guideline cited. These are planning ranges from the published models, not verdicts, and the official state worksheet always controls.
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Estimate the monthly range
100% freeHow your state computes it
- A planning range from the published formula type, not your number. The official state worksheet, with its exact schedule, controls and is what courts use.
- States differ on gross versus net income, and add-ons stack on top: health insurance premiums, childcare, and extraordinary medical costs are usually shared in addition to the base amount.
- Parenting time changes the math: substantial or equal timeshare triggers different worksheets in most states and can reduce the obligation significantly.
- Judges can deviate for documented reasons, and low-income payers get self-support reserves in most guidelines. Support also adjusts: either parent can request modification on a substantial change in circumstances.
Information only, not legal advice. Child support depends on your state's exact schedule, parenting time, add-ons, and judicial discretion. Verify with the official state calculator or counsel.
The four child support formulas states use
Most states (around 41) use income shares: both parents' incomes are combined, a schedule sets the children's basic cost, and each parent owes their proportional slice. The paying parent's slice becomes the transfer payment.
A handful use a percentage of the paying parent's income alone, with Texas (20 to 40 percent of net resources), Wisconsin, Mississippi, Alaska, and Nevada the main examples. New York and New Hampshire apply fixed percentages to the combined income and prorate. Delaware, Hawaii, and Montana use the Melson formula, which protects each parent's self-support reserve before sharing.
| Model | States | What drives the number |
|---|---|---|
| Income shares | ~41 states + DC | Combined income and the state's cost schedule |
| Percentage of obligor income | TX, WI, MS, AK, NV, ND | Paying parent's income and child count only |
| Combined percentage (prorated) | NY, NH | Fixed percentage of combined income, split by share |
| Melson formula | DE, HI, MT | Self-support reserves first, then income sharing |
What gets added to the base amount
The guideline number is rarely the whole obligation. Health insurance premiums for the children, work-related childcare, and extraordinary medical or educational costs are typically allocated between the parents in proportion to income, on top of the base support.
The reverse also exists: most states credit the paying parent for other children they support, for the children's share of certain benefits, and, in many states, for substantial parenting time.
How parenting time changes the number
Once the paying parent's time crosses a state-specific threshold, commonly between 25 and 40 percent of overnights, most income-shares states switch to a shared-placement worksheet that offsets the two obligations against each other. Equal incomes plus equal time can drive support near zero; unequal incomes with equal time still produce a transfer from the higher earner.
This is why the same family can get materially different numbers in neighboring states, and why the estimator above flags timeshare rather than guessing at it. Pair it with the Custody Arrangement Estimator to think through the schedule first.
Modification and enforcement basics
Child support is modifiable, not fixed: a substantial change in circumstances, often defined as a 10 to 20 percent difference from the current order or a set dollar threshold, supports a modification petition, and most states allow an administrative review every three years without proving a change.
Enforcement is the strongest in civil law: wage withholding is the default collection method nationwide, and arrears can trigger tax-refund interception, license suspension, and credit reporting. Arrears generally cannot be retroactively forgiven, which is why filing for modification promptly when income drops matters.
Child support formulas by state
Search any state to see its formula type. Open the estimator above for the range, the computation rows, and the guideline citation.
Frequently asked questions
How is child support calculated?
By your state's formula: most combine both parents' incomes and split the children's scheduled cost proportionally (income shares); a few apply a percentage to the paying parent's income alone, and Delaware, Hawaii, and Montana use the Melson formula. Add-ons for health insurance and childcare stack on top. The estimator shows your state's model and a range.
What percentage of income is child support?
In percentage states it is explicit: Texas starts at 20 percent of net resources for one child, Wisconsin at 17 percent of gross, Mississippi at 14 percent of adjusted gross. In income-shares states there is no fixed percentage; the effective rate usually lands between 14 and 25 percent of combined income for one child and declines as income rises.
Does 50/50 custody mean no child support?
Not automatically. Equal time with equal incomes can zero the transfer, but with unequal incomes most states still order the higher earner to pay, using a shared-placement offset worksheet. A few percentage states adjust differently. The schedule matters as much as the label.
Is child support based on gross or net income?
It varies by state: Texas uses net resources, Wisconsin uses gross, most income-shares states use gross or adjusted gross with defined deductions. The definitions are in the guideline cited by the estimator, and they matter enough to change the number by hundreds of dollars.
What if the paying parent is unemployed or underemployed?
Courts can impute income based on earning capacity, work history, and local wages, so quitting a job does not erase the obligation. Genuine involuntary income drops are grounds for modification, and filing quickly matters because arrears accrue until the order changes.
How long does child support last?
To age 18 or high-school graduation in most states, to 19 in a few, and to 21 in New York and a small group. Support for adult disabled children can continue indefinitely, and college-cost contributions are statutory in some states and contractual in others.
Can parents agree to a different amount?
Yes, within limits: courts review stipulations against the guideline and will approve deviations that are explained and serve the children. Agreements below the guideline get the most scrutiny, and the duty belongs to the child, so parents cannot waive it permanently.
Is child support taxable or deductible?
Neither. Child support is not income to the recipient and not deductible by the payer under federal law, unlike pre-2019 alimony. The dependency exemption and child tax credit allocation are separate questions usually handled in the order or agreement.