01
The Day Count
How many days each parent has, and confirming both cross 91. This is what puts you in the shared formula at all.
Monday - Friday8:30AM - 5PM
OfficesFairfax | Manassas
Child Support / Shared Custody Calculation
Shared Custody Calculation · Virginia
Cross 91 overnights, and the math changes.
Once each parent has the child at least 91 days a year, Virginia switches to the shared custody formula. It accounts for the time you each spend, and the number it produces can surprise both parents.
First call is a conversation, not a commitment.
The Short Answer
When each parent has the child for 91 or more days a year, Virginia uses the shared custody formula in Virginia Code § 20-108.2(G). It adjusts the basic obligation based on each parent's income share and how the days are divided. It usually produces a lower number than sole custody for the higher earner, but rarely zero when incomes are far apart.
How The Math Works
Time enters the equation.
The big difference between the sole and shared formulas is time. The sole custody formula barely cares how many days the paying parent has, as long as it is under 91. The shared formula puts the day count right into the math. The result is that two families with identical incomes can owe very different support depending on the schedule.
What triggers it
The shared custody formula applies when each parent has the child for at least 91 days in a year. A day generally means a 24-hour period with the child. A block of time with the child that is less than 24 hours can count as a half day. Getting the day count right is the first thing we confirm, because it decides which formula applies at all.
How the formula differs
The shared formula starts from the same basic obligation, then raises it by a set factor to reflect the cost of keeping the child in two homes. It then allocates that adjusted amount between the parents based on both their income shares and the share of days each parent has. The two parents' obligations are offset against each other, and one pays the other the difference.
Why it is not automatically lower
Many parents assume that more time means less support, or none. That is the most common misconception in child support. When incomes are close to equal and the time is close to equal, support can be small. But when one parent earns much more, that parent can still owe meaningful support even with a near equal schedule, because the formula is built on income, not just days.
The add-ons still apply. Health insurance and work-related childcare go into the shared calculation the same way they do in sole custody. We run the full math both ways so you can see exactly how the schedule changes the number.
Applies whenEach parent has the child for 91 or more days in a year.
Counting daysA day is generally a 24-hour period; a shorter block can count as a half day.
How it differsRaises the basic obligation, then allocates it by income share and day share.
Common resultLower than sole custody for the higher earner, but rarely zero when incomes differ.
SourceVirginia Code § 20-108.2(G).
The 91-Day Line
The shared custody formula only applies once each parent reaches 91 days a year. A schedule that lands just over or just under that line can change the formula, and the number, significantly.
Source: Virginia Code § 20-108.2(G)
Alisa Chunephisal, Esq.Family Law Attorney
Attorney Insight
A few honest things about shared custody support.
"More time helps, but income drives the number. A high earner with a 50-50 schedule can still owe real support, and that surprises people."
The shared formula rewards time, but not as much as parents expect when there is a real income gap. We run your numbers under both the sole and shared formulas so you can see exactly what the schedule is worth in dollars. Sometimes a few more overnights matter a lot. Sometimes they barely move the number. Either way, you should know before you negotiate.
Questions Parents Ask
Plain answers about shared custody support.
These are the questions parents ask most about the shared formula. If yours is not here, we will run your numbers with you.
Have a specific question?
Call 571.260.0999 or send us a message.
When does the shared custody formula apply?
The shared custody formula applies when each parent has the child for at least 91 days in a year, under Virginia Code § 20-108.2(G). Below that line, the standard sole custody formula applies instead.
A day generally means a 24-hour period, and a block of time under 24 hours can count as a half day.
Does shared custody mean no child support?
Not necessarily. Equal or near-equal time can lower support, but it does not automatically erase it. Because the formula is built on both parents' incomes, a parent who earns significantly more can still owe support even with a 50-50 schedule. Whether you owe, and how much, depends on the incomes and the day count together.
How are days counted for the shared formula?
A day is generally a 24-hour period the child spends with a parent. A block of time with the child that is less than 24 hours can count as a half day. Because the 91-day line decides which formula applies, the counting method can change your number, so it is worth getting right.
Why is shared custody support higher than I expected?
Usually because of the income gap. The shared formula raises the basic obligation to reflect two homes, then splits it by income share and day share. When one parent earns much more, their larger income share can outweigh the time credit, so the number lands higher than a simple time split would suggest.
When You Are Ready
See what the schedule is worth in dollars.
Tell us the incomes and the day count. We will run the sole and shared formulas side by side so you know exactly what the schedule changes. Three offices across Northern Virginia, one phone number.