New Hampshire Child Support Laws (2026): Guidelines & Calculator

New Hampshire calculates child support under the income shares model established by RSA Chapter 458-C, basing the obligation on both parents' combined net income. Each parent's share of that total reflects their proportional contribution to combined income, ensuring the child benefits from resources both households would have provided together. Use the New Hampshire child support calculator below to estimate a guideline amount, or open the full-page New Hampshire child support calculator for a detailed breakdown.

How to Apply for Child Support in New Hampshire

Parents seeking child support in New Hampshire must petition the court for a support order. The Division of Child Support Services (DCSS) within the Department of Health and Human Services provides assistance throughout the process.

Contact Information:

• Main Line: (603) 271-6418
• Toll Free: 1-800-852-3345
• Central Information Unit: (603) 271-4427
• Locate family court offices by county

Services provided by DCSS:

• Locating absent parents
• Establishing paternity
• Establishing support orders
• Collecting and distributing payments
• Enforcing support orders
• Reviewing and adjusting existing orders

To apply, you will need the names and ages of the children, current addresses of both parents, information about any state aid received, and proof of paternity. Parents receiving public assistance automatically receive child support services through DCSS.

Establishing Paternity in New Hampshire

Before a child support order can be issued, legal paternity must be established for children born to unmarried parents. New Hampshire recognizes two methods under state law:

• Voluntary acknowledgment: Both parents sign an affidavit of paternity, typically at the hospital when the child is born or afterward at a vital records office.
• Judicial determination: Either parent or DCSS petitions the court for a paternity order. The court may order genetic testing to confirm biological parentage.

If the father is married to the mother at the time of birth, New Hampshire law presumes he is the legal father. For unmarried parents, establishing paternity is a necessary first step before seeking a child support order.

Contact DCSS at 1-800-852-3345 to begin the paternity establishment process.

How Is Child Support Calculated in New Hampshire?

New Hampshire adopted an income shares model in 2013, replacing the older percentage-of-income approach. Under this model, child support is based on both parents' combined net income, reflecting how the family would have allocated resources for the children if the parents still lived together. The guidelines are set forth in RSA Chapter 458-C.

Determining Net Income

Gross income includes (per RSA 458-C:2):

• Wages, salary, commissions, tips
• Bonuses and annuities
• Social Security benefits
• Trust income, lottery or gambling winnings
• Interest, dividends, investment income
• Net rental income, self-employment income
• Alimony received from a person not party to the current support order
• Pensions and retirement benefits
• Workers' compensation, unemployment, and disability benefits

Note: Regular overtime is excluded if earned at an hourly rate for hours over 40 per week in trades that traditionally pay overtime. Professionals and business owners cannot recharacterize their income as overtime.

Adjusted gross income is calculated by subtracting:

• Court-ordered support actually paid for other children
• 50% of actual self-employment tax paid
• Mandatory (not voluntary) retirement contributions
• Actual state income taxes paid
• Amounts paid for child care or medical support for the children in the current case

Net income is the parents' combined adjusted gross income minus standard deductions published annually by the Department of Health and Human Services. These deductions are based on federal IRS withholding table amounts for federal income tax, FICA, and Medicare.

The Child Support Formula

Under RSA 458-C:3, the total support obligation equals the parents' combined net income multiplied by a percentage that varies based on income level and number of children. The income brackets in the statute are annual combined net income figures, even though the resulting support order is expressed as a monthly amount. The table below summarizes the key guideline percentages:

The NH Department of Health and Human Services publishes a detailed guideline schedule with interpolated percentages between these income levels. That published lookup table is laid out by combined monthly net income, while the percentages themselves are interpolated on an annual basis, so the two are easy to confuse. A family with $8,492 in combined monthly net income (about $101,900 a year) lands at roughly 19.9 percent for one child, not the 25.6 percent top-row rate.

You can also open the full-page New Hampshire child support calculator to estimate your obligation. If your combined income is higher than the top of the published DHHS guideline schedule, contact the Central Information Unit at (603) 271-4427 or 1-800-852-3345 ext. 14427 for guidance.

How Support Is Divided Between Parents

The total child support obligation is divided between parents in proportion to their respective shares of combined income. The obligor's parental support obligation is the proportional share payable to the obligee parent.

For example, if one parent earns 60% of the combined income and the other parent earns 40%, the first parent would be responsible for 60% of the total child support obligation.

Low-Income Provisions

The January 2025 amendments raised the self-support reserve from 115% to 130% of the federal poverty guideline for a single person. For 2026, this translates to approximately $20,748 per year ($15,960 x 130%). Special provisions apply when the obligor's gross income falls below this threshold:

• If gross income is below the self-support reserve and the parent is not voluntarily unemployed or underemployed, a minimum support order of $50 per month may be issued.
• If paying the full guideline amount would reduce the obligor's income below the self-support reserve, support is limited to the difference between the obligor's income and the reserve, but not less than $50 per month.
• Under RSA 458-C:2, incarceration cannot be treated as voluntary unemployment.

Medical Support Obligation

Under RSA 458-C:3(V), the presumptive medical support obligation is 4% of each parent's gross income, unless the court finds this amount unjust or inappropriate. This obligation covers the cost of maintaining health insurance for the children.

Shared Parenting Adjustments (January 2025 Update)

House Bill 1564 (HB 1564), effective January 1, 2025, added significant provisions to RSA 458-C:5 for shared custody situations. These amendments reflect the growing trend of shared parenting in New Hampshire.

Approximately Equal Parenting (Over 40% Each)

When parents meet all of the following conditions:

• Each parent shares 50% of child care costs, uninsured medical expenses, and extracurricular activities
• Parents have substantially similar incomes (the difference between gross monthly incomes is not greater than 10%)
• Parents have an approximately equal parenting schedule (each parent has more than 40% of annual parenting time)

There is a rebuttable presumption that $0 child support is appropriate. This means neither parent owes child support unless evidence shows this would be unjust.

Substantially Shared Parenting (Over 35% Each)

When parents have substantially similar incomes (within 10%) and a substantially shared parenting schedule (each parent has more than 35% of annual parenting time), there is a rebuttable presumption that deviation from the standard guidelines is appropriate. The court will consider the specific circumstances to set a fair amount.

Unequal Incomes with Shared Time

When parents do not have substantially similar incomes but do share custody, the court determines support based on the best interests of the children. The focus is on whether the lower-earning parent can meet child-rearing costs in a comparable manner to the higher-earning parent.

Key rule: With shared or approximately equal parenting and no extraordinary circumstances, a child support order should not result in the obligee parent having a higher adjusted monthly income than the obligor parent after accounting for the support transfer.

How to Modify Child Support in New Hampshire

Under RSA 458-C:7, either parent may request a modification of their child support order:

• Every 3 years without showing a substantial change in circumstances
• At any time when a substantial change in circumstances exists

DCSS is required to notify both parents of their right to request a review at least once every 3 years.

Grounds for Modification

Common grounds for seeking a modification include:

• Significant increase or decrease in either parent's income
• Involuntary job loss, pay cuts, or disability
• Changes in custody or parenting time arrangements
• Changes in the child's needs (medical, educational)
• Changes in the cost of health insurance
• Incarceration or serious illness affecting earning capacity

Key Modification Rules

• Modifications take effect from the date notice was given to the respondent, not the date of the new order.
• If modification results in overpayment, the court must order reimbursement unless doing so would cause undue hardship.
• A new spouse's income is not directly factored into the calculation. However, the court may consider it if the parent is voluntarily unemployed or underemployed.
• Remarriage alone is not sufficient grounds for modification.
• For multiple-child orders, when one child ages out of support, the obligor must petition to modify the order. The termination of support for one child is not automatic because the total support amount must be recalculated for the remaining children.

Child Support Enforcement in New Hampshire

When a parent falls behind on child support payments, DCSS and the courts have multiple enforcement tools available:

Administrative Enforcement Actions

• Income withholding: Automatic wage deductions from the obligor's employer
• License revocation: Driver's licenses, occupational licenses, and professional licenses
• Credit bureau reporting: Delinquent support is reported to credit agencies, affecting credit scores
• Tax refund interception: State, local, and federal tax refunds can be intercepted
• Lottery and gambling winnings interception
• Passport denial or revocation: Available for arrears exceeding $2,500 under federal law
• Property liens: Filed against real and personal property, remaining in effect until arrears are paid
• Financial institution data match: Bank accounts can be identified and levied

Show Cause Hearings and Contempt

If administrative enforcement actions are unsuccessful, the receiving parent or DCSS can petition for a show cause hearing. The obligor must appear in court to explain the failure to pay.

If the court finds the failure to pay was willful, penalties may include fines, jail time, payment of the other party's attorney fees, or compulsory community service.

Criminal Penalties

Failure to pay child support in New Hampshire can result in criminal charges. Under RSA 639:4, a person is guilty of non-support if they knowingly fail to provide support they are legally obliged and able to provide. The offense level turns on the size and age of the arrearage:

• Class B felony (punishable by up to 7 years in prison) if any one of the following is true: the arrearage has remained unpaid for a cumulative period of more than one year; the arrearage is more than $10,000; or the obligor has a prior New Hampshire non-support conviction, or a similar conviction in another state, and the New Hampshire arrearage has remained unpaid for a cumulative period of more than one year.
• Class A misdemeanor (punishable by up to 1 year in jail) in all other cases.

Federal charges under the Deadbeat Parents Punishment Act (18 U.S.C. 228) may also apply if the obligor willfully fails to pay support for a child living in another state and the obligation has remained unpaid for more than 1 year or exceeds $5,000.

When Does Child Support End in New Hampshire?

Under RSA 461-A:14, child support obligations terminate when the child:

• Marries
• Becomes a member of the armed services
• Is emancipated by court order under RSA 461-B
• Reaches age 18

Extended Support for Full-Time Students (Effective July 1, 2025)

Under the amended RSA 461-A:14(IV), if a child is still a full-time student at a secondary school, elementary school, charter school, or home education program at age 18, child support continues until the child graduates or reaches 2 months past age 19, whichever comes first. At that point, all child support obligations, including educational support obligations, terminate automatically without further legal action.

Support for Children with Disabilities

If the parties have a child with disabilities, the court may initiate or continue child support after the child reaches age 18. However, no child support order for a child with disabilities that becomes effective after July 9, 2013, may continue beyond the child's 21st birthday.

College and Post-Secondary Education

New Hampshire does not require parents to pay for college or other post-secondary education. However, if parents voluntarily agree in writing to provide post-18 educational support, the court will enforce that agreement. Read and understand any agreement thoroughly before signing, as voluntary commitments become legally binding.

Emancipation

New Hampshire has an emancipation statute under RSA 461-B. A minor who is at least 16 years old may petition the court for emancipation. If granted, the emancipation order terminates the parents' child support obligation going forward. However, existing child support arrears remain enforceable.

More New Hampshire Laws

• New Hampshire Alimony Laws
• New Hampshire Child Custody Laws
• New Hampshire Divorce Laws