Calcoid

Child Support Calculator

Estimate monthly child support using the Income Shares Model used by 38 US states. Combines both parents' incomes, splits the basic support obligation pro-rata, adds health insurance and childcare, and applies a shared-custody adjustment above 100 overnights per year. Estimate only, not legal advice.

Both parents' gross monthly income and parenting time

The non-custodial parent's pre-tax monthly income. Must be greater than zero.

The custodial parent's pre-tax monthly income. Enter 0 if they have no earned income.

Children shared by both parents. Children with another co-parent are excluded.

Standard "every other weekend plus one weeknight" is ~80 overnights. Shared-custody adjustment kicks in above 100.

Premium attributable to the children only, not the parent policy. Added to the basic support before splitting.

Daycare, after-school care, summer camp tied to a parent working. Added to the basic support.

For display only. The calculator uses a representative composite Income Shares schedule, not your state's exact worksheet.

Estimated monthly child support owed by payer

$918.75

Based on combined income $8,000 and a 62.5% payer income share.

Basic support (table)

$1,470

Total combined obligation

$1,470

Payer's pro-rata share

$919

Health insurance add-on

$0

Childcare add-on

$0

Shared custody adjustment

$0

Step-by-step breakdown

  • Combined gross monthly income: $8000.00. Payer's share of combined income: 62.5%.
  • Basic support for 2 children at this combined income: $1470.00 per month, from the Income Shares schedule.
  • Total combined support obligation: $1470.00. Payer's pro-rata share (62.5%): $918.75 per month.
  • Payer has 80 overnights per year, at or below the 100-night threshold. No shared-custody adjustment is applied.
  • Estimated final monthly child support owed by payer: $918.75.

Legal disclaimer

This is an estimate only, not legal advice. Real court orders depend on your state's official Income Shares worksheet, deviations approved by the judge, and case-specific factors (extraordinary expenses, parenting-time arrangements, imputed income, self-support reserves). Consult a family-law attorney before relying on any number for negotiation, court filings, or enforcement actions.

Combined Income Share Examples

Each parent's share of combined gross income, which is a common input pattern in support calculations.

Parent A Monthly IncomeParent B Monthly IncomeCombined IncomeParent A Share
$2,500.00$2,500.00$5,000.0050%
$3,000.00$3,000.00$6,000.0050%
$4,000.00$2,000.00$6,000.0066.67%
$6,000.00$3,000.00$9,000.0066.67%
$8,000.00$2,000.00$10,000.0080%

Support rules vary by jurisdiction and case facts. Treat the calculator as an estimate, not a court determination.

Frequently Asked Questions about the Child Support Calculator

What is the difference between the Income Shares Model and the Percentage of Income Model?
The Income Shares approach begins with both parents' incomes, estimates the support amount for the child, and allocates it by each parent's income share. A Percentage of Income approach instead applies a percentage to one parent's income. States can modify either approach with parenting time, child-care costs, health insurance, other dependents, income limits, and local rules. This calculator uses an Income Shares estimate for planning only. It does not determine a legal support order, so verify the current guideline and court calculation for your state.
Is this calculator a substitute for a lawyer or my state's official worksheet?
No. This is a planning estimate, not legal advice. Real child-support orders depend on your state's official worksheet (which uses different schedule numbers than the representative composite here), judicial deviations, imputed income for unemployed or underemployed parents, self-support reserves, extraordinary medical or educational expenses, prior support obligations, and tax filing status. Two cases with identical incomes can produce orders that differ by hundreds of dollars per month between states or even between counties. Use this calculator to ballpark the range before negotiation or mediation, but file with your state's official worksheet and a family-law attorney before signing or paying anything.
Why does the support amount vary so much between states?
Each state uses its own schedules, income definitions, self-support reserve, custody adjustment, add-on expenses, caps, and judicial deviations. The calculator's representative formula is not calibrated to any current state worksheet and cannot rank states reliably. Use the official worksheet and current rules for the state with jurisdiction.
What counts as an overnight for shared-custody purposes?
An overnight is not universally defined as a full 24-hour period. State worksheets may count nights, days, or parenting-time equivalents under their own rules. The calculator uses a simple annual overnight count and a 100-night internal threshold. That threshold is not a current legal rule for any specific state.
When does the shared-custody adjustment actually reduce the payment?
In this calculator, the adjustment starts above 100 entered overnights and grows linearly, capped at a 50 percent reduction. That is an internal model, not a federal standard or a substitute for a state's shared-custody worksheet. A real order can use a different threshold, formula, expense allocation, or no automatic reduction.

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