Legal calculator

Child Support Estimator, Monthly Support Calculation

Estimate monthly child support payments using income shares and percentage of income models. Understand how income, custody time, and children count affect support.

Published by · Reviewed against primary-source formulas

This calculator provides estimates only. Child support is determined by courts applying your state's specific guidelines. Consult a family law attorney for accurate calculations.

$
$

Income Shares model only

%

% of overnights (typical: 20% = every other weekend)

$

Insurance premiums for child only

$

Daycare, after-school care

Base Support

–

Before adjustments

Healthcare Add

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Non-custodial share

Childcare Add

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Non-custodial share

Est. Monthly Total

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Combined obligations

How CalcMesh estimates child support

Most U.S. states use the income-shares model, which estimates the support both parents would have provided together and apportions it by income. We apply this common approach using both parents’ incomes, the number of children and parenting time.

Because each state publishes its own guideline schedule, our result is an estimate only; the model we use is described in our methodology. Consult an attorney for your state.

Income Shares Model

Used by ~40 states. Both parents' incomes are combined to find total "available income for the child." The guideline table sets a base support amount. Each parent contributes proportionally based on their share of combined income. The non-custodial parent pays their proportion to the custodial parent.

Percentage of Income Model

Used by Texas, Wisconsin, and several other states. Only the paying parent's income matters. Support is a fixed percentage: 1 child = 20%, 2 children = 25%, 3 = 30%, 4 = 35%, 5+ = 40% of net income.

Texas Percentage Guidelines

Children % of Net Income
120%
225%
330%
435%
5+40%

Disclaimer: This is an educational estimate only. Courts apply state-specific worksheets, local rules, and judicial discretion. Consult a licensed family law attorney in your state for accurate guidance.

Methodology & Assumptions

This calculator implements standard formulas drawn from primary-source authorities. Values are point-in-time estimates; consult a licensed professional for high-stakes decisions. See the per-input definitions and source citations below.

How this works

Computations are deterministic and run client-side, no inputs leave your browser. Formulas are derived from standard published formulas for the calculator's domain (mortgage, taxes, energy, conversions, etc.). When the underlying agency publishes updated rates or thresholds we refresh defaults and update the page's lastmod timestamp.

Frequently Asked Questions

How is child support calculated?
Most states use the Income Shares model: both parents' incomes are combined, and each contributes proportionally. A support guideline table converts the combined income to a base support amount, then each parent pays their share based on income percentage. The non-custodial parent typically pays their share to the custodial parent.
What income is included?
All income sources count: wages, salary, bonuses, commissions, self-employment income, rental income, investments, and even unemployment benefits. Some states impute income if a parent is voluntarily unemployed.
Can child support be modified?
Yes, if there's a "substantial change in circumstances" - usually a 10-15% change in income, custody changes, or new children. Either parent can petition the court for modification. Orders typically auto-review every 3 years in many states.
Does custody percentage affect support?
Yes significantly. States calculate parenting time (overnights) and reduce support obligations as the non-custodial parent spends more time with the child. At 50/50 custody, support may be minimal or zero depending on the income gap.

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This page identifies the inputs, method, and limitations behind its estimates. Calculator outputs are not professional advice and should be checked against the relevant primary source for a consequential decision. This calculator's formula and defaults are drawn from standard published sources for its domain, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.

Inputs, defaults, and authoritative sources
Input Default Source / authority
All inputs Domain-typical defaults Editorial methodology, CalcMesh 2026