Virginia Child Support Guideline Worksheets: DC-637, DC-638, and DC-640

Virginia calculates child support with a formula, and these three worksheets are the formula. Which one you use depends entirely on the custody arrangement — and picking the wrong one can change the number by hundreds of dollars a month.

Which worksheet applies

DC-637 — sole custody. Use this when one parent has the children more than 90 days a year and the other has fewer. Despite the name, “sole custody” here is a support term, not a custody term. You can have joint legal custody and still use the sole custody worksheet.

DC-640 — shared custody. Use this when each parent has the children for more than 90 days a year. The 90-day threshold is a cliff, not a slope. At 90 days you are on DC-637; at 91 you are on DC-640, and the number often drops sharply. This is why parents fight over what looks like a trivial difference in the schedule.

DC-638 — split custody. Use this when each parent has primary physical custody of at least one child.

How the calculation works

Virginia uses an income shares model under Va. Code § 20-108.2. In outline:

1. Determine each parent’s gross monthly income — including salary, bonuses, commissions, self-employment income, pensions, and in some cases the fair market value of employer benefits
2. Add them together to get combined monthly gross income
3. Look up the basic child support obligation for that combined income and number of children on the statutory schedule
4. Add work-related childcare costs and the children’s health insurance premium
5. Divide the total in proportion to each parent’s share of combined income
6. On DC-640, apply the shared custody adjustment based on each parent’s days

The result is presumptively correct. A judge can deviate, but must state written reasons based on the statutory deviation factors.

What counts as income

More than people expect. Overtime, bonuses, rental income, and unemployment benefits count. Military allowances — BAH and BAS — count, which routinely surprises service members in Hampton Roads and Northern Virginia and produces a support figure far higher than base pay alone would suggest.

If a parent is voluntarily unemployed or underemployed, the court can impute income based on earning capacity rather than actual earnings.

How a “day” is counted

For the 90-day threshold, a day generally means a 24-hour period of custody. Partial days can count in some circumstances but the rules are technical, and courts vary. If your schedule is near the threshold, count carefully before you agree to it.

Common errors

• Using gross income for one parent and net for the other
• Omitting the health insurance premium, or including the whole family premium rather than the children’s portion
• Counting childcare that is not work-related — the statute covers employment-related care
• Using DC-640 when one parent is at exactly 90 days
• Forgetting support paid for children from another relationship, which may be deductible