How is child support calculated?

Most states use an "Income Shares" model: combined parental income × state percentage based on number of children, then divided by each parent's income proportion.

What income is counted?

Gross income from all sources: salary, bonuses, commissions, self-employment, rental income, and investment income. Some states allow deductions for taxes and other support obligations.

Can child support be modified?

Yes, either parent can request modification if there's a significant change in circumstances (income, custody, expenses). Most states require at least 15-20% change.

What expenses are included?

Basic support covers housing, food, clothing, and general needs. Additional expenses like health insurance, childcare, education, and extracurricular activities are added separately.

Legal Calculators

Child Support Calculator

Estimate child support payment obligations based on both parents' income levels, custody percentage, number of children, health insurance costs, and state guidelines for family law planning. Features accurate monthly payment calculations, income share model analysis, custody schedule impact, and support obligation estimates for family budgeting, divorce planning, and legal proceedings for parents, attorneys, and family court mediators.

How to Use the Child Support Calculator

Use the Child Support Calculator to child support payment obligations based on both parents' income levels, custody percentage, number of children, health insurance costs, and state guidelines for family law planning. Features accurate monthly payment calculations, income share model analysis, custody schedule impact, and support obligation estimates for family budgeting, divorce planning, and legal proceedings for parents, attorneys, and family court mediators.. Enter your values to get accurate, instant results tailored to your situation.

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Child Support Guide

State guidelines & calculations

Expert Tips

Income Shares Model (Most States): 40+ states use income shares: Each parent pays proportional to income. Combined $10K monthly, Parent A earns 60% = 60% of obligation. Federal guideline assumes both incomes support children equally.
Parenting Time Reduces Payment: Spending 146+ nights/year (40%+) typically reduces obligation 25-50% depending on state. Example: 50/50 custody cuts support 30-50%. High custody percentage = lower payment due to direct care costs.
Additional Expenses Beyond Basic: Basic support covers food, clothing, housing. Add-ons: Health insurance (80-100%), childcare (80-100%), extracurriculars (50-50 split). Total obligation often 30-50% higher than basic calculation.
Modification Requires 15-20% Income Change: Courts typically require 15-20% income change or 3 years since last order before modifying. Job loss, promotion, new child qualify. File modification within 90 days of change—not retroactive beyond filing date.
Imputed Income for Unemployed: Courts impute income if parent voluntarily unemployed. Based on education, work history, local wages. Example: Engineer making $120K quits job—court imputes $100K+ regardless of actual income. Cannot avoid support by not working.
Tax Treatment: Child support is NOT tax deductible for payer, NOT taxable income for recipient. Unlike alimony which is deductible/taxable. Calculate post-tax impact: $2K support costs payer full $2K (no deduction), recipient keeps full $2K (no tax).

Essential Fundamentals — How calculations work

Calculation Methods

Income Shares Model: Most common (40+ states). Combines both parents' income, applies guideline percentage (17-33% depending on # of children), then splits by income proportion. Example: Combined $15K/mo, 2 kids (25% = $3,750). Parent A earns 70% → pays $2,625. Parent B earns 30% → pays $1,125.
Percentage of Income: Texas, Wisconsin, others. Non-custodial parent pays fixed % of gross income. Texas: 1 child 20%, 2 children 25%, 3 children 30%. Simpler but ignores custodial parent's income. Example: Non-custodial earns $8K/mo, 2 kids → $8K × 25% = $2,000/mo regardless of other parent's income.
Parenting Time Adjustment: Most states reduce obligation based on overnight custody percentage. Thresholds vary: Some adjust at 30%, others at 40-50%. Example: 50/50 custody (183 nights each) typically reduces obligation 30-50% because both parents bear direct costs equally.

Income & Deductions

Gross Income Definition: Includes wages, bonuses, commissions, self-employment profit, rental income, dividends, military allowances, unemployment. Excludes child support received, TANF/welfare. Courts can impute income if voluntarily unemployed or underemployed.
Allowed Deductions: Pre-existing child support (other children), mandatory retirement contributions, union dues. NOT allowed: Voluntary retirement, debt payments, new spouse expenses. Net income = gross - limited deductions. Most calculations use gross income.

Advanced Strategies — Modifications & planning

Modification Strategies

When to Modify: File when income changes 15-20% (job loss, raise, new job), custody changes (more/less parenting time), child ages out, new medical needs. Modifications not retroactive—apply from filing date. File immediately after qualifying change to minimize loss.
Document Income Changes: Unemployment: Keep termination notice, unemployment statements. Income decrease: Tax returns, pay stubs for 6+ months. Self-employed: Profit/loss statements for 12-24 months. Strong documentation required—courts skeptical of undocumented claims.
Negotiated Agreements: Parents can agree to amounts different from guidelines if court approves. Higher/lower than calculated. Must be in child's best interest. Example: Exchange lower support for more custody time, college savings, or other benefits. Court retains final approval power.

Frequently Asked Questions

How is child support calculated?: Most states use an "Income Shares" model: combined parental income × state percentage based on number of children, then divided by each parent's income proportion.
What income is counted?: Gross income from all sources: salary, bonuses, commissions, self-employment, rental income, and investment income. Some states allow deductions for taxes and other support obligations.
Can child support be modified?: Yes, either parent can request modification if there's a significant change in circumstances (income, custody, expenses). Most states require at least 15-20% change.
What expenses are included?: Basic support covers housing, food, clothing, and general needs. Additional expenses like health insurance, childcare, education, and extracurricular activities are added separately.