NC Child Support Calculator: Income, Worksheets, and Adjustments

The NC child support calculator is a free online tool from the North Carolina Department of Health and Human Services that estimates a monthly support obligation using the same Income Shares formula judges apply in court. You enter each parent’s gross monthly income, pick the worksheet that matches your custody arrangement, add a few child-related expenses, and the tool produces a number that closely tracks what a court would order in a guideline case.¹

The estimate is only as good as the inputs. A wrong worksheet, an incomplete income figure, or a missed adjustment can throw the result off by hundreds of dollars a month.

Running the Calculator

The tool lives on the NC DHHS child support site at ncchildsupport.ncdhhs.gov. No account or registration is required; the eChild Support portal that asks you to register is a separate case-management system for tracking payments and uploading documents, not for running calculations.²

Open the guidelines page and choose the worksheet that fits your custody situation. The form loads with placeholder numbers already in the fields, so replace every entry with your actual figures before running the calculation. Fill in each parent’s gross monthly income, the monthly cost of the child’s health insurance, work-related childcare, and any other applicable adjustments. Click Compute. You can print the completed worksheet and bring it to mediation or to an attorney. The online worksheets mirror the official court forms (AOC-CV-627 for primary custody, AOC-CV-628 for shared custody), so the output translates directly into court filings.

Picking the Right Worksheet

North Carolina uses three worksheets, and the choice is driven by overnights per year.

Worksheet A (Primary Custody): One parent has the child the majority of the time and the other has fewer than 123 overnights per year. This is the most common setup.
Worksheet B (Joint or Shared Custody): Both parents have the child for at least 123 overnights per year, roughly one-third of the calendar. The formula adjusts for the fact that both households are covering direct expenses for the child.³
Worksheet C (Split Custody): Each parent has primary custody of at least one of the children in the case. For example, the older child lives mainly with one parent and the younger with the other.

Worksheet B has an important limit. The 123-overnight threshold is necessary but not sufficient. The worksheet instructions warn that a parent who merely hosts the child more than 122 nights, without actually paying for the child’s expenses during those stays, should use Worksheet A instead.³ Pick the wrong worksheet and a court will reject the number.

What to Enter as Income

Gross monthly income drives the whole calculation. Under the guidelines, gross income is income before any deductions for federal or state taxes, Social Security, Medicare, health insurance premiums, or retirement contributions. It covers wages, salaries, commissions, bonuses, self-employment earnings, rental income, dividends, interest, Social Security benefits, veterans’ benefits, military pay, pensions, workers’ compensation, and personal injury awards.¹

Non-cash benefits count too. Free housing, a company car, or similar in-kind perks that meaningfully reduce a parent’s personal living expenses go into gross income. Self-employment income is calculated as gross receipts minus ordinary and necessary business expenses, which is narrower than the deductions a tax return would allow.

Several categories stay out. Means-tested public assistance like TANF (Work First), food stamps, and Supplemental Security Income doesn’t count. Neither does a current spouse or live-in partner’s income, child support received for children from a different case, or alimony received from the other parent in the same proceeding.¹

When a Parent Isn’t Earning What They Could

If a court finds a parent is voluntarily unemployed or underemployed in bad faith to lower support, it can assign “potential income” and run the calculation on what that parent could be earning rather than what they actually earn. The court weighs work history, education, occupational qualifications, and job opportunities in the community. Where a parent has no recent work history or vocational training, the guidelines set a floor: potential income cannot be less than minimum wage for a 35-hour work week. The court must also consider whether caring for a young child or a physically or mentally disabled child in the home legitimately limits a parent’s ability to work. Incarceration cannot be treated as voluntary unemployment.¹

If you’re running an estimate on someone else and suspect they’ve reduced their income deliberately, entering their actual pay will understate the eventual court order.

Adjustments That Move the Number

The calculator has specific lines for a handful of expenses that can meaningfully change the result.

Health insurance premiums: Only the portion covering the child. If a parent pays $400 a month for a family plan but the child’s share is $120, enter $120.
Work-related childcare: Daycare, after-school care, and summer programs that let a parent work or look for work are added to the basic obligation and split proportionally between the parents.
Extraordinary expenses: Unusual recurring costs, such as expenses tied to a child’s special medical needs or other documented necessities beyond ordinary spending.
Pre-existing support obligations: Court-ordered child support already being paid for children from another relationship is deducted from gross income before the calculation runs.

Each entry maps to a specific line on the state worksheet, and the calculator applies them automatically.¹

Where the Calculator’s Estimate Stops Being Reliable

The tool applies the state’s Basic Child Support Schedule, which was last updated effective January 1, 2023. That schedule covers combined adjusted gross incomes up to $40,000 per month, or $480,000 per year. Above that ceiling, the schedule doesn’t apply and a judge sets support based on the child’s reasonable needs and each parent’s ability to pay. If your combined income is close to or above that line, treat the calculator’s output with caution.¹

At the other end, a self-support reserve protects very low-income paying parents. When the paying parent’s income is near or below the federal poverty level for one person, the reserve reduces or eliminates the obligation so that parent can cover basic living costs. The current threshold is $1,133 per month, based on the 2022 federal poverty guidelines. This is not a free pass. The guidelines set a minimum obligation of $50 per month in most of these cases.¹

Even inside the schedule, a judge can order a different amount. The guideline number carries a legal presumption of correctness, but the court can deviate if it finds by the greater weight of the evidence that the formula would fall short of the child’s reasonable needs or exceed them given each parent’s ability to pay. To deviate, the judge must make written findings covering the presumptive guideline amount, the child’s reasonable needs and each parent’s ability to pay, why the guideline amount is inadequate or excessive, and the basis for the different amount ordered.⁴ Common deviation scenarios include significant medical expenses not captured on the extraordinary-expenses line, crushing debt from a medical crisis, or combined income above the schedule ceiling.

Using the Calculator to Review an Existing Order

The calculator is also the fastest way to see whether an existing order is ripe for modification. Either parent can ask the court to modify support at any time by showing changed circumstances.⁵

A useful bright-line rule applies to older orders. If the existing order was entered at least three years ago and re-running the calculator with current incomes produces a number that differs by 15 percent or more from the current obligation, that gap is presumed to be a substantial change of circumstances warranting modification. No other proof is required beyond the math.¹

For orders less than three years old, you need to show a genuine change: job loss, a significant and lasting income shift, or a change in custody. A modification takes effect from the date the motion is filed, not the date the circumstances changed, so filing promptly matters. Support that accrued under the old order remains owed. Federal law also requires state child support agencies to offer a review at least every three years when either parent requests one or when the case involves public assistance.⁶

Run the calculator with today’s incomes and today’s custody schedule. Compare the result to what’s actually being paid. That comparison tells you whether a modification is worth pursuing.

1
North Carolina Department of Health and Human Services. North Carolina Child Support Guidelines
2
North Carolina Department of Health and Human Services. North Carolina Child Support Worksheet A (Primary Custody)
3
North Carolina Judicial Branch. AOC-CV-628 – Child Support Obligation Joint or Shared Physical Custody
4
North Carolina General Assembly. North Carolina Code 50-13.4 – Action for Support of Minor Child
5
North Carolina General Assembly. North Carolina Code 50-13.7 – Modification of Order for Child Support or Custody
6
eCFR. 45 CFR 303.8 – Review and Adjustment of Child Support Orders