How New Hampshire Calculates Child Support
New Hampshire uses the Income Shares model for child support. The governing law is New Hampshire Revised Statutes Annotated Chapter 458-C, along with the New Hampshire Child Support Guidelines. New Hampshire combines both parents' net income to determine the total monthly obligation and splits it proportionally. The guidelines apply to all child support proceedings in the state.
New Hampshire's approach follows the core Income Shares principle: the total cost of raising the children is estimated from combined parental income, and each parent funds their proportional share.
The New Hampshire Child Support Formula
New Hampshire's calculation follows four steps.
Step one is determining each parent's monthly net income. Step two is combining both net incomes to produce the combined monthly net income. Step three is finding the Basic Support Obligation in New Hampshire's schedule using the combined income and number of children. Step four is calculating each parent's income share percentage and applying it to the obligation.
A practical example: Parent A earns $5,000 per month. Parent B earns $2,500. Combined income is $7,500. Parent A's income share is 66.7 percent. If New Hampshire's schedule sets the Basic Support Obligation at $1,300 for two children at $7,500 combined income, Parent A's base obligation is $867 per month before adjustments and add-ons.
New Hampshire also has a self-support reserve provision. When a paying parent's income is low enough that the standard formula would leave them unable to meet their own basic needs, the court adjusts the obligation to maintain a minimum self-support level.
What Counts as Income in New Hampshire
RSA 458-C:2 uses a broad income definition. Courts include wages, salaries, commissions, bonuses, overtime, self-employment income, rental income, pension and retirement distributions, Social Security benefits, SSDI payments, unemployment compensation, workers' compensation, and income from any other regular source.
Courts can impute income to a parent who is voluntarily unemployed or underemployed based on work history, qualifications, and the local job market.
New Hampshire allows deductions from income before combining incomes: court-ordered child support currently being paid for children from other relationships and court-ordered alimony from prior orders. These deductions reduce each parent's net income before proportional shares are calculated.
Step-by-Step: How to Use This Calculator
Step 1. Get your net monthly income. Start with gross income from all sources, then subtract federal income tax, Social Security and Medicare as New Hampshire's guidelines allow.
Step 2. Subtract existing court-ordered obligations. If you are currently paying child support or alimony from a prior order, subtract those amounts from your net income.
Step 3. Estimate the other parent's net monthly income using the same method.
Step 4. Enter the number of children covered by this order.
Step 5. Enter your parenting time percentage. Count actual overnights per year and divide by 365. New Hampshire applies a credit when the paying parent has significant overnight time with the children, scaling upward as overnights approach 50 percent.
Step 6. Add healthcare costs. Enter the monthly premium for the children's health insurance.
Step 7. Add childcare costs. Enter monthly work-related childcare expenses.
Step 8. Review the full breakdown before accepting the result.
Parenting Time Adjustments in New Hampshire
New Hampshire applies a parenting time credit when the paying parent has significant overnight parenting time. The credit reflects the direct costs that parent incurs during their time with the children.
At standard visitation levels, the credit is minimal. As overnights increase toward 50 percent, the credit grows. At near-equal parenting time, both parents' obligations are considered and the higher earner pays the net difference. New Hampshire courts also address transportation costs for parenting time in long-distance arrangements. Significant travel costs may be allocated between the parents or factored into a deviation.
Add-On Expenses in New Hampshire
New Hampshire adds healthcare premiums and work-related childcare costs to the base obligation, allocated proportionally by income share. Courts may also address extraordinary medical expenses and educational costs on a case-by-case basis.
Reading Your Results
The results show each parent's net income, combined net income, the Basic Support Obligation from New Hampshire's schedule, income share percentages, the parenting time credit if applicable, add-on costs, and the final monthly obligation.
Confirm that prior support obligation deductions appear correctly in the net income line before accepting the result.
After You Get Your Estimate
New Hampshire courts follow the RSA 458-C guidelines in all standard cases. Deviation is allowed when the guideline amount would be unjust or inappropriate. Courts consider each parent's financial resources, the child's needs, travel costs, and any relevant special circumstances.
Modification requires a substantial change in circumstances. A 15 percent or more change in the calculated obligation is a commonly applied threshold. Income changes, parenting time shifts, and changes in healthcare or childcare costs are the most frequent grounds.
A licensed New Hampshire family law attorney can review your calculation and advise on deviations or modifications. Many offer a free consultation.