Child Support Calculator
Estimate monthly child support using the Income Shares Model — the standard adopted by most U.S. states. Results are estimates only; consult a family-law attorney for legal advice.
Formula (Income Shares Model)
1. Combined Income = NCP Gross Income + CP Gross Income
2. Basic Child Support Obligation (BCSO)
BCSO = Combined Income × Income Share %
(1 child = 17%, 2 = 25%, 3 = 29%, 4 = 31%, 5 = 33%, 6+ = 35%)
3. Total Obligation = BCSO + Healthcare Premium + Work-Related Childcare
4. NCP's Share = Total Obligation × (NCP Income ÷ Combined Income)
5. Parenting-Time Credit (if NCP has ≥ 92 overnights/year):
Credit = (Overnights ÷ 365) × 1.5 × NCP's Share [capped at 50% of NCP's Share]
6. Final Order = NCP's Share − Parenting-Time Credit
Assumptions & References
- Uses the Income Shares Model adopted by ~40 U.S. states (e.g., California, Florida, New York, Texas).
- Income share percentages are based on the Betson-Rothbarth expenditure tables widely referenced in state guidelines.
- The parenting-time credit formula follows the shared-custody adjustment used in states such as Colorado and Washington (threshold: 92+ overnights ≈ 25% parenting time).
- Inputs use gross monthly income before taxes; some states use net income — verify your state's rules.
- Extraordinary expenses (healthcare, childcare) are added to the BCSO before apportioning, per standard Income Shares methodology.
- This calculator does not account for: pre-existing support orders, self-employment deductions, imputed income, or state-specific low-income adjustments.
- References: Child Support Guidelines — Income Shares Model, U.S. Dept. of Health & Human Services (OCSE); Betson-Rothbarth Child Cost Estimates (2010).