Estimate child support
your state's official formula.
Income Shares · Percentage of Income · Melson Formula, 3 models, 9 verified state calculators, side-by-side state comparisons. Free, no registration.
Income Shares
43
states use this model
Percentage of Income
5
states use this model
Melson Formula
3
states use this model
Live calculators
9
interactive, verified
The national picture
43 of 51 US jurisdictions (84%) use the Income Shares model, the dominant approach nationally, but even within that shared model the one-child base rate ranges from 13% in Washington to 25% in Vermont, a 1.9x spread for the same formula family.
According to PlainChildSupport's state guideline dataset.
- 43
- of 51 states use Income Shares
- 13%–25%
- one-child base-rate range nationally
- 1.9x
- gap between lowest and highest base rate
- 9
- states with a verified interactive calculator
The 3 Child Support Formula Models
Every US state uses one of three models to calculate child support. Your state's model determines which parent's income matters, and how much.
43 States
Both parents' incomes are combined. A support obligation is determined from a schedule based on total income, then split proportionally between parents.
Typical range (1 child): 17–22% of combined income
View 43 states →5 States
A fixed percentage of the non-custodial parent's income is applied. Simpler than Income Shares, only the obligor's income matters.
Typical range (1 child): 14–20% of obligor income
View 5 states →3 States
A three-step formula: first ensures each parent's self-support needs, then calculates primary child support, then adds a standard-of-living adjustment (SOLA).
States: DE, HI, MT
View 3 states →Interactive Calculators
Phase 1: State-specific calculators available for the 10 largest states by population.
What Factors Affect Child Support?
- 💰
Both Parents' Incomes
Most states consider gross or net income of both parents.
- 🏠
Parenting Time
40%+ overnight time with the non-custodial parent typically triggers a credit.
- 👶
Number of Children
Obligations scale with each additional child, but not proportionally.
- 🏥
Health Insurance
The parent paying premiums typically gets a credit against the obligation.
- 🏫
Childcare Costs
Work-related childcare expenses are typically split proportionally.
- 📚
Educational Expenses
Private school and extraordinary educational costs may be added to the base.
Guides
Child Support Formulas Explained
Income Shares vs Percentage vs Melson, what each means for you.
How to Modify a Child Support Order
When and how to request modification after a substantial change.
Interstate Child Support: UIFSA
When parents live in different states, which state controls?
Understanding Imputed Income
Courts can assign income to voluntarily unemployed parents.
Deviation Factors by State
Circumstances that allow judges to depart from guideline amounts.
Important Disclaimer
This calculator provides estimates for informational purposes only. Actual child support amounts may differ based on judicial discretion, deviation factors, and current state guidelines. Consult a family law attorney in your state for legal advice.
Frequently Asked Questions
How is child support calculated?
Child support is calculated using your state's statutory guidelines, which are based on one of three formula models: Income Shares (most states, both parents' incomes combined), Percentage of Income (Mississippi, Nevada, North Dakota, Texas, Wisconsin, fixed % of the non-custodial parent's income), or the Melson Formula (Delaware, Hawaii, Montana, complex hybrid). Each state has a specific worksheet and income schedule.
How accurate is PlainChildSupport's calculator?
The calculator produces estimates using each state's published guideline percentages. Real child support orders involve precise financial disclosure, deductions for health insurance and childcare, adjustments for parenting time, and judicial discretion. Always treat calculator results as a starting point, not a final answer.
Which states have interactive calculators on PlainChildSupport?
PlainChildSupport provides interactive calculators for the 10 largest states. All 50 states plus DC have guideline pages explaining the formula model used, key percentages, and links to official state resources.
Is this legal advice?
No. PlainChildSupport provides informational tools and publicly available guideline data only. This is not legal advice. Child support law is complex and varies by state and individual circumstance. Always consult a licensed family law attorney in your state before making legal decisions.
About this data
How PlainChildSupport works, and why you can trust these numbers
What this site is
PlainChildSupport is a plain-language reference for the 50-state child support guideline landscape. Each state page identifies its statutory formula model (Income Shares, Percentage of Income, or the Melson Formula), key percentages, and links to the official state statute or agency guideline document, so every figure traces back to a citable source.
Editorial process
- Source. Research each state's published child support statute, income schedule, and guideline worksheet, cross-referenced against NCSL model summaries and the federal Office of Child Support Services.
- Verify. Confirm the formula model and statutory percentages directly against the state code citation before publishing a state profile.
- Publish. Build a per-state guideline page and, for the 10 largest states, an interactive calculator using the published percentages, always labeled as an estimate.
Editorial independence & corrections
The PlainChildSupport editorial team is independent and accepts no advertising or sponsorship from family-law practices. Found a figure that looks wrong? Reach us via the contact page and we will verify against the cited state statute. See our methodology for full source attribution.
Frequently asked
How is child support calculated?
Child support is calculated using your state's statutory guidelines, which are based on one of three formula models: Income Shares (most states, both parents' incomes combined), Percentage of Income (Mississippi, Nevada, North Dakota, Texas, Wisconsin, fixed % of the non-custodial parent's income), or the Melson Formula (Delaware, Hawaii, Montana, complex hybrid). Each state has a specific worksheet and income schedule.
How accurate is PlainChildSupport's calculator?
The calculator produces estimates using each state's published guideline percentages. Real child support orders involve precise financial disclosure, deductions for health insurance and childcare, adjustments for parenting time, and judicial discretion. Always treat calculator results as a starting point, not a final answer.
Which states have interactive calculators on PlainChildSupport?
PlainChildSupport provides interactive calculators for the 10 largest states. All 50 states plus DC have guideline pages explaining the formula model used, key percentages, and links to official state resources.
Is this legal advice?
No. PlainChildSupport provides informational tools and publicly available guideline data only. This is not legal advice. Child support law is complex and varies by state and individual circumstance. Always consult a licensed family law attorney in your state before making legal decisions.
Research
Original analysis from our editorial team, every statistic derived from our own database. See all research.
Three Formulas, One Country: How US Child Support Calculations Diverge by State
43 of 51 US states use Income Shares, 5 use Percentage of Income, and 3 use the Melson self-support-reserve model, a mechanical split that produces radically different outcomes at identical incomes.
ResearchWhy Iowa Collects 68.4% of Child Support While Mississippi Collects 49.3%
PlainChildSupport's enforcement data shows a 19.1 percentage-point gap between the best-performing and worst-performing US states on child support collection rate, a structural divergence that compounds to billions in unpaid support.
ResearchOnly 10 of 51 States Publish Verified Child Support Calculators
Of 51 US jurisdictions, only 10 publish official calculators that PlainChildSupport has verified against statute. The other 41 rely on PDF worksheets, third-party tools, or formulas parents must execute themselves.
Related Guides
Editorial context for the plainchildsupport dataset, methodology, comparisons, and deep dives into the underlying records.