New Hampshire uses hard-coded percentages of combined NET income per RSA 458-C: 25% (1 child), 33% (2), 40% (3), 45% (4+). Self-support reserve: 130% of FPL.
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New Hampshire calculates child support using the Percentage of combined NET income established under RSA 458-C (Updated Jan 2025, HB 1564). This is a statutory formula that leaves limited room for judicial discretion on the base calculation amount, ensuring consistency and predictability for families across the state.
Statutory percentage x combined net income x obligor share.
The calculation begins with determining each parent's net disposable income, which includes virtually all sources of income minus taxes, mandatory payroll deductions, and certain hardship deductions. The court then applies the statutory formula using the time each parent has primary physical responsibility for the children and the applicable income allocation brackets.
Beyond the base formula amount, New Hampshirerequires additional contributions for mandatory add-on expenses. These typically include childcare costs necessary for the custodial parent's employment or education, uninsured healthcare expenses for the children, and in some cases, educational and travel costs. These add-ons are split between parents in proportion to their respective incomes.
Primary statute: RSA 458-C (Updated Jan 2025, HB 1564)
25% for 1 child, 33% for 2, 40% for 3, 45% for 4+.
Combined NET income.
Self-support reserve: 130% of FPL (~$1,628/mo).
NH has NO state income tax — only federal deductions.
Hard-coded percentages (not schedule-based).
No state income tax — higher net income.
Updated Jan 2025 (HB 1564).
Answer a few questions about your income, custody, and children. Get your personalized estimate.
Residency Requirement
1-year residency required
Mandatory Waiting Period
None
No-Fault Ground
Irreconcilable differences
State Income Tax
NO STATE INCOME TAX (I&D tax repealed Jan 1, 2025).
New Hampshire uses the Percentage of combined NET income under RSA 458-C (Updated Jan 2025, HB 1564). New Hampshire uses hard-coded percentages of combined NET income per RSA 458-C: 25% (1 child), 33% (2), 40% (3), 45% (4+). Self-support reserve: 130% of FPL.
Key factors include both parents' income, the number of children, custodial time share, mandatory add-on expenses (childcare, health insurance), and any applicable deductions. 25% for 1 child, 33% for 2, 40% for 3, 45% for 4+.
Yes. Either parent can request a modification if there has been a material change in circumstances, such as a significant change in income, custody arrangements, or the needs of the child. The court will recalculate support using the same statutory formula.
Statutory percentage x combined net income x obligor share.
Get a personalized child support calculation based on New Hampshire's actual statutory formula.
Start My Free New HampshireEstimate →This tool provides educational estimates based on New Hampshire family law and does not constitute legal advice. Child support calculations are approximations of the statutory formula and may differ from court-ordered amounts. Consult a licensed New Hampshire family law attorney before making decisions. Primary statute: RSA 458-C (Updated Jan 2025, HB 1564).