Child Support Percentage Calculator: Annual Obligation From Income
Estimate a child support obligation from net income and a state guideline percentage — a quick figure for budgeting, not a legal calculation.
Adjust the inputs and select Calculate for a full breakdown.
Compare Common Scenarios
How the numbers shift across typical situations for this calculator:
| Scenario | Annual child support | Income net of support |
|---|---|---|
| 17% of $60,000 (NY 1 child) | 10,200 | 49,800 |
| 25% of $80,000 (NY 2 children) | 20,000 | 60,000 |
| 29% of $120,000 (NY 3 children) | 34,800 | 85,200 |
| 20% of $45,000 | 9,000 | 36,000 |
How This Calculator Works
Enter annual net income and the state guideline percentage (NY: 17% for one child, 25% for two, etc.). The calculator multiplies the two to give the annual support amount and shows what's left of net income.
The Formula
Percentage of an Amount
Amount is the base value, Percentage is the rate applied to it
Worked Example
On $60,000 net income with a 17% NY one-child guideline, child support is $10,200 a year — about $850 a month. The figure leaves $49,800 of net income before any other obligations. Actual orders almost always differ from this simple estimate because most state formulas factor in parenting time, healthcare, child care, and the other parent's income.
Key Insight
This calculator gives a back-of-envelope figure. Real child support orders are calculated by state-specific worksheets that account for the income-shares model (combining both parents' incomes), parenting-time adjustments, healthcare and child care costs split, and special needs. Family-law attorneys and state-specific online calculators give legally meaningful estimates; this one gives the rough order of magnitude for planning.
Child support formulas 2024
INCOME SHARES MODEL (38 states).
Combine both parents' income.
Apply % from state schedule per # kids.
Allocate proportional to each parent's income share.
Non-custodial pays share to custodial.
CA, NY, FL, TX, OH, MA, MI, GA, NJ, etc.
PERCENTAGE OF INCOME (7 states).
% of non-custodial parent's income only.
WI, AK, MS, ND, NE, NV, TX (TX uses both).
Typical: 1 kid 17-20%, 2 kids 25-29%, 3 kids 29-35%.
MELSON FORMULA (3 states).
DE, HI, MT.
Self-support reserve + needs-based.
Most complex; protects low-income parents.
GUIDELINES vs DEVIATION.
Federal law requires guidelines.
Court may deviate 15-25% of cases.
Adjustments + state examples
SHARED CUSTODY ADJUSTMENT.
Typically reduces obligation if non-custodial >30% time.
States vary: 30-40% time threshold.
EXTRAORDINARY EXPENSES.
Health insurance premiums.
Childcare (work-related).
Private school / extracurriculars.
Special needs.
Split proportionally.
INCOME DEFINITION.
Gross + bonus + commissions.
Self-employment Schedule C adjustments.
Imputed if voluntarily under-employed.
TAX TREATMENT.
Not deductible to payor.
Not income to recipient.
Custodial parent typically claims CTC + dependent.
STATE EXAMPLES.
CA: Income Shares, online guideline calculator.
TX: 20% net 1 kid, 25% 2 kids (Percentage).
NY: 17% combined 1 kid, 25% 2 kids.
U.S. child support guidelines (2024)
Reference state formulas + percentages.
| Item | Detail |
|---|---|
| Income Shares states | 38 |
| Percentage of Income states | 7 |
| Melson Formula states | 3 |
| TX % 1 kid (net) | 20% |
| TX % 2 kids (net) | 25% |
| TX % 3 kids (net) | 30% |
| NY % 1 kid (combined) | 17% |
| NY % 2 kids (combined) | 25% |
| WI % 1 kid | 17% |
| WI % 2 kids | 25% |
| Shared custody threshold | 30-40% time |
| Court deviation rate | 15-25% |
| Tax to payor | NOT deductible |
| Tax to recipient | NOT income |
Income Shares (38 states) most common. % varies by state + # kids. Shared custody, extraordinary expenses, imputed income, court deviation substantially adjust. Not tax-deductible (post-2017). OCSE + NCSL + IRS data.
Frequently Asked Questions
How is child support calculated?
Varies by state. Some states (NY, IL, ND) use simple percentage of obligor's income. Most others use income-shares model (both parents' incomes combined, then split by parenting time). The flat-percentage approach here is the simpler version.
What is a typical guideline percentage?
Percentage-of-income states: 1 child often 17% to 22%, 2 children 25% to 30%, 3 children 29% to 35%, 4 children 31% to 39%, 5+ children 35%+. Income-shares states use different math entirely.
Does parenting time affect it?
In most states yes — substantially. Equal-parenting-time arrangements often produce very different support amounts than primary-custodian arrangements. This simple calculator ignores parenting time; real orders don't.
Is child support tax-deductible?
No — child support is not tax-deductible by the payor and is not taxable to the recipient under US federal law (since 2019). Alimony has different and changing tax treatment.
Can the amount be modified?
Yes — child support orders can be modified when circumstances materially change (job loss, large income increase, custody change, child's needs). Modifications require a court order; informal changes are not legally enforceable.
When is this calculator unreliable?
Less reliable when state-by-state formula variance (Income Shares vs Percentage vs Melson), when shared physical custody adjustments (>30% time threshold typical), when extraordinary expenses (medical, special needs, private school), when self-employment income calculation (Schedule C adjustments), when imputed income for under-employed parent, when tax credit + benefit allocation (CTC, EITC), or when court deviation from guidelines (15-25% of cases).
References & Authoritative Sources
- U.S. Office of Child Support Enforcement (OCSE) — Federal Child Support Resources · consulted June 1, 2026 · Federal HHS division
- Internal Revenue Service (IRS) — Tax Topics + Publications · consulted June 1, 2026 · Federal tax authority
- National Conference of State Legislatures (NCSL) — Child Support Guidelines by State · consulted June 1, 2026 · State legislative resource
Related Calculators
Methodology & Review
Child support percentage models federal/state guidelines. U.S. 2024: most states use 'Income Shares Model' (38 states) — % of combined income by # children; 'Percentage of Income Model' (7 states); 'Melson Formula' (3 states). Federal CSE program oversight. Substantial state variation in formulas + adjustments. RELIABILITY: Reliable for ballpark guideline estimates. Less reliable for (a) state-by-state formula variance (Income Shares vs Percentage vs Melson), (b) shared physical custody adjustments (>30% time threshold typical), (c) extraordinary expenses (medical, special needs, private school), (d) self-employment income calculation (Schedule C adjustments), (e) imputed income for under-employed parent, (f) tax credit + benefit allocation (CTC, EITC), (g) court deviation from guidelines (15-25% of cases).
Updated