Child Support and Custody in New Hampshire: How Parenting Time Affects Support

New Hampshire overhauled its child support rules effective January 1, 2025. The biggest change: how much parenting time each parent has now directly triggers different support presumptions. A 50/50 schedule with similar incomes can result in zero child support. An unequal schedule with disparate incomes defaults to the standard guidelines. Understanding these tiers matters because they shape both your custody negotiations and your financial planning.

How Standard Child Support Is Calculated

Under RSA 458-C, child support starts with each parent's gross monthly income — wages, self-employment, rental income, trust distributions, Social Security benefits, and commissions. From that, the court subtracts specific deductions to arrive at adjusted gross income:

• Court-ordered support or alimony paid for other families
• 50% of self-employment taxes
• Mandatory, non-discretionary retirement contributions
• State income taxes actually paid (New Hampshire has no state income tax on wages, but taxes interest and dividends above certain thresholds)
• Health insurance premiums and work-related childcare costs

The combined adjusted net income of both parents is multiplied by a statutory percentage based on the number of children: 19-25.6% for one child, 26-35.5% for two children, and 31-42.5% for three children. The total obligation is then split proportionally based on each parent's share of the combined income.

The 2025 Parenting Time Tiers

HB 1564 created a tiered system linking child support to the parenting schedule. Here's how it works when both parents equally share childcare costs, uninsured medical expenses, and agreed-upon extracurricular activities:

Tier 1: Zero support presumption. If parents have substantially similar incomes (within 10% of each other) AND an approximately equal parenting schedule (each parent has more than 40% of overnights — at least 146 per year), there's a rebuttable presumption of zero child support. Neither parent pays the other.

Tier 2: Downward deviation presumption. If parents have substantially similar incomes AND a substantially shared schedule (each parent has more than 35% of overnights — at least 128 per year), there's a presumption that the standard guideline amount should be reduced. The exact reduction depends on the circumstances.

Tier 3: Lifestyle parity standard. If parents have disparate incomes (more than 10% difference) AND either an equal or substantially shared schedule, the court determines support with one paramount consideration: whether the lower-earning parent can maintain the child in a similar lifestyle to the higher-earning parent's household. Standard guidelines may or may not apply.

Tier 4: Standard guidelines apply. If the parenting schedule is unequal (less than 35% shared time), there's a strong presumption that the standard calculation governs.

The Income Backstop Rule

To prevent gaming, RSA 458-C:5, I(h)(1)(E) includes a strict guardrail: in shared or equal parenting arrangements, the final support order cannot result in the receiving parent ending up with more adjusted monthly income than the paying parent, after accounting for federal taxes, Social Security, and Medicare.

This backstop prevents situations where a lower-earning parent could use the support formula to achieve a higher net income than the parent paying support.

The Self-Support Reserve

If a paying parent's gross income falls below 130% of the federal poverty guideline for a household of one, the court imposes a minimum support order of $50 per month — provided the parent isn't voluntarily underemployed or unemployed. This floor ensures some contribution while preventing the paying parent from falling below subsistence level.

Medical Support and Extra Expenses

Beyond the base support calculation, both parents share a medical support obligation. Under RSA 458-C:3, V, each parent is presumed to contribute 4% of their gross monthly income toward the child's health insurance premiums and uninsured medical, dental, and optical costs.

Work-related childcare, summer camp, and agreed-upon extracurricular activities are typically split 50/50 or proportionally by income. The parenting plan should explicitly address how these variable expenses are divided — vague language creates disputes later.

Tax exemptions and child tax credits don't automatically go to the parent with more overnights. Courts expect parents to share these benefits — typically alternating years or splitting them by child if there are multiple children. Your parenting plan must specify which parent claims which child in which tax years.

Why This Matters for Your Custody Negotiation

The 2025 changes mean parenting time and child support are now tightly linked. A parent seeking more overnights may be motivated partly by the financial implications — and a parent resisting equal time may fear the zero-support presumption. Courts are aware of these dynamics, and a judge who suspects a parent is seeking 50/50 primarily to avoid paying support will scrutinize that parent's actual involvement in the child's daily life.

The strongest position: propose a schedule that genuinely reflects the child's needs and your availability, and let the support calculation follow from there.

The New Hampshire Child Custody & Parenting Plan Guide includes a child support worksheet that walks through the 2025 tier system, an overnight counting tool to determine which tier applies to your schedule, and a variable expense tracking worksheet for medical, childcare, and extracurricular costs.

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