This article is informational only. It is not legal advice and does not create an attorney-client relationship. Virginia child support law changes, and every case has facts that can move the number. Confirm your specific situation with the Fairfax County Juvenile and Domestic Relations District Court (JDR), the Virginia Division of Child Support Enforcement (DCSE), or a licensed Virginia attorney.
Fairfax County / Virginia Child Support Calculator: How Virginia’s Guideline Is Actually Figured
Virginia sets child support with one statewide formula, not a Fairfax-specific one. Under Va. Code § 20-108.2, the court adds both parents’ monthly gross income together, looks up that combined number on the state’s schedule (which now runs to $42,500 a month in combined income after a July 2025 update), finds the “basic” support obligation for the number of children involved, and splits that obligation between the parents based on each one’s share of the combined income. Health insurance and qualifying child-care costs get added on top. Fairfax County JDR and Circuit Court judges apply this exact calculation — Fairfax’s own role is intake, filing, and enforcement, not a separate math.
The worksheet Fairfax judges actually use
The state form is Form DC-637, “Child Support Guidelines Worksheet,” for sole-custody cases, and Form DC-640 for shared-custody cases. Both are published by the Virginia Judicial System and both cite Va. Code § 20-108.2 directly on the form. The DC-637 worksheet runs through these steps:
- Line 1: each parent’s monthly gross income
- Lines 2–4: adjustments for spousal support already being paid or received, support for other children, and allowable deductions such as reasonable business expenses for self-employed parents
- Line 5: each parent’s “available income” and the combined total
- Line 7: the basic obligation pulled from the statutory schedule, plus amounts for health coverage and work-related child care
- Line 9–10: each parent’s percentage share of the combined income, applied to the total obligation
What counts as gross income (and what doesn’t)
Va. Code § 20-108.2(C) defines gross income broadly: wages, salaries, commissions, bonuses, dividends, pensions, rental income, capital gains, Social Security benefits, and even gifts, prizes, or awards all count. It excludes public assistance payments (TANF, SSI, food assistance), child support received for other children, and income a paying parent earns specifically to pay down a court-ordered arrearage. Self-employed parents subtract reasonable business expenses and half of any self-employment tax paid before their income enters the formula — a commonly missed adjustment on the worksheet.
The $42,500 combined-income cap and the 2025 update
Virginia’s schedule of basic support obligations is a table: combined monthly gross income on one axis, number of children on the other. For years the table topped out at $35,000 in combined monthly income. Legislation passed in 2025 (Senate Bill 805, codified as an amendment to § 20-108.2) raised that ceiling to $42,500 and adjusted the dollar amounts at every income tier — the first change of that scale since 2014. For combined incomes above $42,500 a month, the statute has the court add a set percentage of the excess income to the support amount calculated at the $42,500 mark, rather than extrapolating off the table. If your combined income sits above that ceiling, this is a case where getting the add-on percentage right is worth an attorney or DCSE double-check.
Health insurance and child care get added on top
The basic table amount isn’t the whole obligation. Under § 20-108.2(E), the cost of the child’s share of health, dental, or vision coverage gets added to the basic obligation, calculated as the difference between individual and family-plan premiums divided among covered dependents. Coverage is only required to come from a parent’s plan if it’s available at “reasonable cost,” defined in the statute as no more than 5% of that parent’s gross income. Work-related child care costs get added the same way under § 20-108.2(F), capped at what a licensed provider would reasonably charge.
Shared custody changes the formula
When a parent has the child for more than 90 days of the year, Virginia switches from the DC-637 sole-custody worksheet to the DC-640 shared-custody worksheet. The shared formula takes the basic table amount, multiplies it by 1.40 to account for the added cost of maintaining two homes, and divides that inflated number by the percentage of custody days each parent actually has. The parent with the larger calculated obligation pays the net difference to the other. This produces a different result than sole custody on the same income and child count — a common source of confusion when parents compare worksheets informally.
The presumptive minimum: $68 a month
At the bottom of the schedule, for combined monthly income of $350 or less, Virginia sets a presumptive minimum obligation of $68 a month for one child (higher for additional children). Even where the calculated obligation would come out lower, $68 is presumed unless an exemption applies. Exemptions exist for parents who are institutionalized in a psychiatric facility, imprisoned for life without parole, medically verified as totally and permanently disabled with no ability to pay, or otherwise involuntarily unable to earn income. Separately, if a paying parent’s income is at or below 150% of the federal poverty guideline, a judge can set the obligation below $68 after hearing evidence, as long as doing so doesn’t leave the other household unable to cover basic housing and necessities for the child.
How a Fairfax County case actually moves
New cases are generally filed where the paying parent lives, often alongside custody and visitation, in the JDR court covering that jurisdiction. Fairfax’s JDR Domestic Relations intake line (703-246-3040) schedules the appointment; filing fees apply. Parents who’d rather go the administrative route, especially when the other parent lives out of state, can request an order through DCSE instead. If a support order already exists and circumstances change — a job loss, a big income change, a shift in custody — either parent can petition to modify it, but the court requires proof of a “material change in circumstances,” and Fairfax routinely refers modification petitions to mediation before setting a hearing. DCSE also reviews existing orders roughly every three years on request. For that process without hiring counsel, see this guide to modifying an order without a lawyer, and for how another state’s calculator handles similar inputs, compare the Mississippi calculator breakdown.
Running your own numbers
Because the Virginia formula depends on several moving pieces — income adjustments, the combined-income schedule, health coverage, child care, and custody-day percentages — a plain percentage calculator won’t reproduce what a Fairfax JDR judge orders. The Navigating Child Support calculator walks through the same line items as the DC-637 and DC-640 worksheets. For the fields pre-built into a fillable, savable form, the forms app covers Virginia’s DC-637 and DC-640 alongside other states, and the book Navigating Child Support walks through what documentation JDR asks for at intake.
Frequently asked questions
Does Fairfax County use a different child support formula than the rest of Virginia?
No. Fairfax County JDR and Circuit Court apply the same statewide guideline under Va. Code § 20-108.2 that every Virginia court uses. What differs locally is the filing process, intake scheduling, and which forms clerks hand out.
What is the minimum child support order amount in Virginia?
The schedule sets a presumptive minimum of $68 a month for one child at the lowest combined-income bracket, with exemptions for parents who are institutionalized, imprisoned for life, permanently disabled with no ability to pay, or below 150% of the federal poverty level.
What happens if combined parental income is above $42,500 a month?
The statutory schedule tops out at $42,500 in combined monthly gross income. Above that, the court adds a percentage of the income above $42,500 to the support amount calculated at the $42,500 level, rather than reading a table value directly. High-income cases are a common candidate for attorney review.
How is shared custody calculated differently?
When a parent has more than 90 days of custody or visitation per year, Virginia uses Form DC-640 instead of DC-637. The basic table obligation is multiplied by 1.40, then divided according to each parent’s share of custody days, and the parent owing more pays the net difference to the other.
Can I change a Fairfax County child support order later?
Yes, either parent can petition to modify an existing order, but Fairfax JDR requires evidence of a material change in circumstances since the last order and typically refers the case to mediation first. DCSE-administered orders can also be reviewed roughly every three years.
Disclaimer: This article summarizes Virginia’s child support guideline for general informational purposes. It is not legal advice, does not account for every exception in your case, and should not be relied on as a substitute for advice from a licensed Virginia attorney or a determination from DCSE or the court. Figures cited reflect the guideline schedule and presumptive minimum in effect as of this writing and are subject to change through future legislation or the state’s quadrennial guidelines review.
