Child Support Calculator 2026
Free child support and child maintenance calculator for the United States, Canada, United Kingdom, Australia, and New Zealand. Calculate support based on official guidelines, income, custody arrangements, and additional expenses.
Choose Your Country
United States
All 50 states supported with state-specific guidelines
Canada
Federal Child Support Guidelines & Quebec Model
United Kingdom
Child Maintenance Service 6-step calculation
Australia
Services Australia Costs of Children Table
New Zealand
Inland Revenue formula assessment
State-specific child support guidelines apply. Calculations may vary by state.
Enter Parent A's parenting time percentage (0-100). Parent B's percentage will be calculated automatically.
United States
Income Shares Model (Most States)
Calculates total support based on combined parental income, then divides proportionally. Accounts for custody time, health insurance, childcare, and special expenses.
Percentage of Income (TX, WI)
Texas: 20% for 1 child, 25% for 2, 30% for 3. Wisconsin uses similar percentages applied to the paying parent's net income.
Federal Child Support Guidelines
Table-based amounts determined by province, number of children, and paying parent's income. Includes Section 7 special expenses (childcare, medical, education).
Quebec Model
Quebec uses its own formula considering both parents' incomes, custody time, and a basic parental contribution based on children's needs.
Child Maintenance Service (CMS) 6-Step Formula
Uses gross weekly income with rates: Nil (under £7/week), Flat (£7-£100), Reduced (£100-£200), Basic (£200-£800), Basic Plus (£800-£3,000). Shared care nights (52+) reduce payments.
Services Australia 8-Step Formula
Calculates Child Support Income (income minus self-support amount), determines care-to-cost percentage conversion, uses Costs of Children Table based on combined income and children's ages, then calculates each parent's share.
IRD Formula Assessment
Uses formula: (Income % − Care Cost %) × Child Expenditure. Deducts living allowance ($29,909), uses Child Expenditure Tables based on income brackets and children's ages. Requires 28% care for recognition, 35% to receive payments.
Income
Both parents' gross or net income (varies by country). Some jurisdictions impute income if a parent is voluntarily unemployed.
Number of Children
Support typically increases with more children, though not proportionally. Children's ages may also affect calculations (older children cost more in some models).
Custody/Care Time
Shared custody reduces support obligations. Different countries have different thresholds (e.g., 28% in NZ, 52 nights in UK).
Health Insurance
Cost of providing health insurance for children is factored into US calculations. Other countries may have public healthcare.
Childcare & Education
Work-related childcare costs and education expenses can be added as special or extraordinary expenses in most jurisdictions.
Special Circumstances
Courts can deviate from guidelines for special needs children, high-income parents, or other extraordinary circumstances.
United States
United Kingdom
New Zealand
For tax and income definitions used in support calculations, see our Sources page.