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.

According to the U.S. Internal Revenue Service and the National Institute of Standards and Technology, more than 1,000 published rate, threshold, and conversion reference values update annually across tax, mortgage, and engineering domains that CalcMesh formulas trace to. The CalcMesh registry listed 53 calculators across 9 categories as of August 2026. See our methodology for derivation standards and refresh cadence.

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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

–

Non-custodial share

Childcare Add

–

Non-custodial share

Est. Monthly Total

–

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.

Labelled scenario, percentage model arithmetic

Educational worksheet math only (not a court order). Texas-style percentage path with paying-parent net proxy:

  • Paying parent gross monthly $4,000; tool’s percentage model uses its net/gross assumption shown on the results.
  • One child at 20% of the model’s net base → if net ≈ $3,200, base ≈ $640/mo before healthcare/childcare add-ons.
  • Healthcare $150 and childcare $0: non-custodial share of healthcare follows the model’s split (often ~income share).
  • Income-shares path with receiving parent $2,500 combines incomes first - the same inputs do not equal the percentage path; switch the model dropdown to see both.

After you estimate

What to do with the numbers

  • Treat the output as a worksheet preview; your state schedule and overnight credit control the order.
  • Toggle Income Shares vs Percentage - the two models are not interchangeable.
  • Enter healthcare/childcare as the child-only amounts the guideline worksheet asks for.
  • For a filing decision, take the printout to a licensed family-law attorney in the order’s state.

Methodology & Assumptions

This statutory-estimate tool applies published model formulas to the incomes and allowances you enter. Court worksheets control real orders—this is orientation math only.

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

How this statutory-estimate node runs

Support and means-test estimators apply published model formulas to your stated incomes. Court worksheets control the real order. Published domain formulas govern the identities; when an agency updates rates or thresholds we refresh defaults and the page lastmod.

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.

This page identifies the inputs, method, and limitations behind its estimates. CalcMesh does not publish lender, insurer, provider, or plan fee schedules. Any monetary output is calculated from the inputs shown on the page, not a current quote. Compare a fee, rate, or term with the governing agreement or disclosure before a consequential decision. Calculator outputs are not professional advice. Statutory estimates here apply model formulas to stated incomes—no court worksheet is filed. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.

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