Child support in New Hampshire.
What the state’s own guideline says, where the number comes from, and the one figure that moves it more than anything you will argue about.
See a different stateNew Hampshire
New Hampshire combines both parents' net incomes, applies a percentage from a statutory table that shrinks as income rises, and then divides the result between the parents according to their shares of that combined income. Work-related childcare and a medical support component are folded into the calculation rather than billed separately.
How New Hampshire works out the number
Authority: N.H. RSA ch. 458-C, Child Support Guidelines (RSA 458-C:2 definitions, 458-C:3 the formula and percentages, 458-C:5 special circumstances and adjustments, 458-C:7 modification)New Hampshire uses percentages of parenting time, not raw overnight counts. "Approximately equal" means more than 40 percent of parenting time for each parent; "substantially shared" means more than 35 percent for each (RSA 458-C:2, VIII-c). Where the parents have substantially similar incomes, share expenses equally and have an approximately equal schedule, "there is a rebuttable presumption that a $0 child support obligation is appropriate." With a substantially shared schedule and similar incomes, there is a presumption that some deviation is appropriate. And where incomes differ, an adjustment "should not result in the obligee parent having higher adjusted monthly income than the obligor parent."
Use the state’s own calculator, not ours
New Hampshire publishes this itself, free. It is called Child Support Guidelines Worksheet (NHJB-2101-F, published by the Judicial Branch; DHHS publishes a matching worksheet). RSA 458-C:3-a requires that "At ev. We are not going to build a competing calculator and ask you to trust it — this is the one a judge will recognize.
Open the New Hampshire calculator →What goes into the calculation
What counts as income
Gross income under RSA 458-C:2, IV includes wages, salary, commissions, tips, annuities, Social Security benefits, trust income, and "lottery or gambling winnings," plus self-employment earnings. New Hampshire has an unusual overtime carve-out: "no income earned at an hourly rate for hours worked, on an occasional or seasonal basis, in excess of 40 hours in any week shall be considered as income." That protects hourly workers who pick up extra shifts; it does not shelter the self-employed or business owners. Bonuses and second-job earnings are otherwise included. From gross income the statute allows deductions including court-ordered support paid for others, "Fifty percent of actual self-employment tax paid," mandatory retirement contributions, state income taxes, and allowable childcare and medical support amounts.
When a judge can treat you as earning more
We could not confirm how this state handles a parent a judge believes is under-earning on purpose.
If you do not earn much
There is both a floor and a reserve. The minimum support order is "$50 per month, unless the court determines that a lesser amount is appropriate" (RSA 458-C:2, V). The self-support reserve is defined as "130 percent of the federal poverty guideline for a single person living alone" (RSA 458-C:2, X). If the obligor's income drops below the reserve after the support calculation, the obligation is reduced to the difference between the reserve and the obligor's adjusted income, but not below the minimum order.
Childcare and health insurance
"Allowable child care expenses" means "actual work-related child care expenses for the children to whom the order applies," and they are accounted for in the adjusted gross income calculation rather than added on afterward. For medical, RSA 458-C:3, V provides that the court "shall establish and order a reasonable medical support obligation for each parent. The presumptive amount of a reasonable medical support obligation shall be 4 percent of the individual parent's gross income."
Private school, special needs, activities
RSA 458-C:5, I lists special circumstances that can justify an adjustment, including "extraordinary medical, dental or education expenses" of a child, the economic consequences of a stepparent or stepchildren, the disposition of the marital home, tax consequences, and unusually high or low income.
When a judge can depart from the number
The guideline figure is presumed correct, and the party who wants to move off it carries the load: "The party relying on the provisions of this section shall demonstrate special circumstances by a preponderance of the evidence" (RSA 458-C:5, II), with the court making written findings.
Two surprises here. New Hampshire ignores occasional or seasonal overtime past 40 hours a week for hourly workers — that is genuinely rare, and it means picking up extra shifts to get through a hard year should not raise your support. And the college rule is absolute: a New Hampshire judge cannot order you or your ex to pay for college unless the two of you wrote it into an agreement. Whatever you sign now is what you get.
Later on
When it ends
RSA 461-A:14, IV: support continues "until the dependent child for whom support is ordered marries, or becomes a member of the armed services, or is emancipated pursuant to an order of emancipation under RSA 461-B, or reaches the age of 18 years, unless the child is still a full-time student at a secondary or elementary school, charter school, or a home education program… at the age of 18, then child support shall continue until the child graduates or until 2 months after the child reaches the age of 19, whichever is first." For a child with disabilities the court may continue support past 18, but an order effective after July 9, 2013 "may [not] continue after the child reaches age 21."
College and support after 18
New Hampshire says no in the statute itself. RSA 461-A:14, V: "No child support order shall require a parent to contribute to an adult child's college expenses or other educational expenses beyond the completion of high school, except as provided in RSA 461-A:21." RSA 461-A:21 is the narrow exception that lets a court give effect to the parents' own written agreement about college costs. If college matters to you, put it in the agreement — a judge cannot impose it later.
Changing the amount later
Two paths. A party may request modification "3 years after the entry of the last order for support, without the need to show a substantial change of circumstances," or at any time by showing a substantial change of circumstances (RSA 458-C:7, I). If a modification produces an overpayment, "the court shall order, absent a showing of undue hardship, the obligee to directly reimburse the obligor."
How far back a change can reach
RSA 461-A:14, VIII: "No modification of a support order shall alter any arrearages due prior to the date of filing the motion." A modification reaches back to the filing date at the earliest, and past-due amounts already accrued cannot be wiped out.
What we could not confirm
- The self-support reserve is set by formula — 130 percent of the federal poverty guideline for one person — and the state publishes the actual dollar figure in an annual guidelines book we could not open. Get the current-year number from the DHHS calculator or the guidelines book before you rely on it. We also could not confirm New Hampshire's written standard for imputing income to a parent who is not working, or the state's published enforcement tools.
- 2 official pages we tried to read refused automated access. We did not try to get around the block, so some detail above comes from a different official source rather than the one we would have preferred.
Compare all fifty states
The overnight thresholds, the ending ages and the college rules, side by side.