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Child Support Calculator

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Estimate child support payments using the income shares model (used in 40+ US states) and percentage-of-income model. Multi-jurisdiction reference.

🌍 Multi-Jurisdiction✔ Income Shares Model

👨‍👧 Child Support Calculator

Results update instantly as you type

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Estimated Monthly Child Support
$0
Income Shares Model estimate
Monthly Support
$0
Annual Total
$0
Paying Parent Share
0%
% of Paying Income
0%
⚠️ Estimates vary greatly by jurisdiction. Courts have discretion to deviate from guidelines. Always consult a family law attorney for your specific case.

How to Use the Child Support Calculator

1

Enter both parents' gross monthly incomes

Input pre-tax monthly earnings for both parents. The Income Shares model used by most US states combines both incomes to determine the total child support obligation.

2

Enter the custody arrangement

Specify the non-custodial parent's annual overnight visits. More than 146 overnights per year (40% of the year) typically triggers a parenting time adjustment that reduces the basic obligation.

3

Add childcare and medical costs

Include monthly work-related childcare costs and health insurance premiums paid specifically for the child. These are added directly on top of the basic support amount.

4

Select your state

Each state uses its own guidelines and economic table. The calculator applies the appropriate Income Shares or Percentage of Income model for your jurisdiction.

How Child Support Is Calculated

Child support guidelines vary significantly by country and state/province. The two dominant models in common-law jurisdictions are:

Income Shares Model (40+ US States)

Both parents' incomes are combined. The total child support obligation is determined from state-published tables. Each parent pays their proportionate share. For example, if the paying parent earns 62.5% of combined income, they pay 62.5% of the total obligation.

Percentage of Income Model (Some US States, rough international guide)

Child support is a fixed percentage of the paying parent's income: typically 17% for 1 child, 25% for 2, 29% for 3, 31% for 4 (varies by state). Texas, Wisconsin, and several other states use this model.

📐 Income Shares Formula

Support = (Payer Income ÷ Combined Income) × Total Obligation × Custody Factor
Total= Combined income mapped to state guideline table
Share= Paying parent % of combined income
Custody= Reduced if significant parenting time (50/50 = shared calc)

Frequently Asked Questions

Child support in the US is calculated using either the Income Shares model (used by most states, considering both parents' incomes) or the Percentage of Income model. Courts factor in each parent's gross income, custody time, work-related childcare costs, and health insurance premiums. Every state has its own statutory guidelines — a judge can deviate from the guidelines only with written justification.
Yes. Child support orders can be modified when there is a material change in circumstances — such as a significant change in either parent's income, the child's needs, custody arrangement changes, or the paying parent losing employment. The process involves returning to court (or the maintenance court in SA).
In most jurisdictions, failure to pay court-ordered child support can result in wage garnishment, license suspension, contempt of court charges, and in serious cases, imprisonment. In SA, contempt of a maintenance court order is a criminal offence.
Child support is calculated at the state level — each state uses its own formula. Most states use either the Income Shares Model (both parents' income combined, support proportional to share) or the Percentage of Income Model (support is a percentage of the non-custodial parent's income only). Factors include incomes, custody split, health insurance, and childcare costs.
Yes. Either parent can petition for modification if there's a substantial change in circumstances — typically a 15–20% or more change in income, change in custody arrangement, or significant change in the child's needs. Courts review modifications periodically; in most states, you can request review every 3 years without proving changed circumstances.
Generally no — child support is based on the biological or legal parents' incomes, not a stepparent's income. However, if remarriage significantly changes a parent's financial situation (e.g., expenses decrease substantially), it could indirectly affect a modification request. Consult a family law attorney in your state for specific guidance.
⚠️ Disclaimer This calculator provides estimates for informational purposes only. Not legal or financial advice. Consult a qualified professional for your specific situation.

Sources & Methodology

Calculations are based on the most current publicly available data from authoritative government and industry sources: