Child Support Estimator

Estimate a preliminary monthly child support amount using figures from your jurisdiction's current child support guidelines.

Important: There is no single U.S. child support formula. States and territories use different guideline models, income definitions, custody adjustments, deductions, credits, and deviation rules. This tool therefore does not invent a nationwide rate. Use the official figures required by your jurisdiction.

Your entries stay in your browser. We do not store or sell your data.

Choose the guideline method

Income Shares Uses both parents' incomes and an official basic support obligation. Percentage of Income Applies an official guideline percentage to the paying parent's income.

Check your state or territory's current guidelines if you are unsure which method applies.

Enter the guideline figures

Parent 1 monthly guideline income

Use gross or net income according to your jurisdiction's rules.

Parent 2 monthly guideline income

Enter the monthly income figure used by your official worksheet.

Parent expected to pay support Choose the parent whose preliminary transfer amount you want to estimate.

Official basic child support obligation

Enter the combined monthly basic obligation for the children covered by this calculation.

Additional monthly expenses allocated by income share

For example, qualifying child care or medical costs, but only if your jurisdiction instructs you to divide them in proportion to income.

Your Estimate

Preliminary monthly support share

$0 per month

Paying parent's income share 0%

Share of basic obligation $0

Share of entered add-ons $0

This is not an official child support order. The actual amount may change because of parenting time, custody arrangements, low income rules, other children, medical support, direct payments, tax issues, deductions, deviations, income limits, judicial findings, or other rules in your jurisdiction.

See how this was calculated

How this child support estimator works

Child support guidelines are not uniform across the United States. Federal regulations require each state to establish its own guideline for setting and modifying child support orders.

Because of those differences, this estimator does not contain a made-up national child support table. Instead, it performs the arithmetic after you enter the applicable figure from your own jurisdiction's official guideline.

Income Shares formula

In an Income Shares calculation, the parents' guideline incomes are combined and each parent's proportional share is calculated.

Paying parent's income share = Paying parent's income ÷ Combined parental income Preliminary support share = Paying parent's income share × (Official basic obligation + qualifying prorated expenses)

In plain English, the tool finds what percentage of the combined parental income belongs to the paying parent, then applies that percentage to the amounts you entered.

Percentage of Income formula

Base support estimate = Paying parent's guideline income × Official guideline percentage

The percentage itself must come from the current rules for the jurisdiction involved. This estimator does not assume one.

What to do with this result

Compare it with your jurisdiction's official child support worksheet or calculator.
Check whether your jurisdiction applies a parenting time or shared custody adjustment.
Check how child care, health insurance, extraordinary medical costs, and support for other children are treated.
Use the estimate for planning rather than treating it as a confirmed court ordered amount.

Why might another calculator give a different result?

Another calculator may use different income definitions, custody formulas, income limits, low income adjustments, child care treatment, medical support rules, deductions, rounding methods, or deviation provisions. Some jurisdictions also use a completely different guideline model.

Important limitations

This estimator does not determine which state's or territory's law applies.
It does not automatically retrieve your jurisdiction's current support schedule or percentage.
It does not calculate shared parenting or parenting time adjustments.
It does not determine allowable income deductions or imputed income.
It does not determine whether an expense legally qualifies as an addition, credit, or deviation.
It does not replace an official guideline worksheet, court order, child support agency calculation, or legal advice.

Methodology

The estimator separates local legal rules from universal arithmetic. For Income Shares calculations, it determines each parent's proportion of the combined entered income and applies the paying parent's proportion to the official basic obligation and any qualifying prorated expenses supplied by the user.

For Percentage of Income calculations, it multiplies the paying parent's entered guideline income by the official percentage supplied by the user. Values are calculated with JavaScript in the browser and displayed to two currency decimal places.

No local rate, threshold, income table, custody adjustment, minimum support amount, maximum support amount, or legal classification is assumed by the tool.

Sources

45 CFR § 302.56, federal requirements for state child support guidelines.
National Conference of State Legislatures, overview of major child support guideline models.
NCSL Child Support Tutorial, explanation of Income Shares, Percentage of Income, and Melson approaches.
California Child Support Services, an example of an official jurisdiction-specific guideline calculator and its limitations.

Methodology last reviewed: September 22, 2026.