How does Virginia calculate child support under the Income Shares Model?

Virginia uses the Income Shares Model under Va. Code § 20-108.2. First, the court determines each parent's monthly gross income (wages, bonuses, self-employment, benefits, etc.). Gross income is adjusted by subtracting spousal support paid, adding spousal support received, subtracting child support for other children, and deducting self-employment business expenses and one-half of self-employment tax to calculate Adjusted Gross Income (AGI). Both parents' AGIs are combined, and the Combined Monthly AGI and number of children are used to look up the Basic Child Support Obligation on the statutory schedule. For income amounts falling between schedule rows, linear extrapolation is required. Health insurance premiums and work-related childcare costs are added to the Basic Obligation. Each parent's share is prorated based on their percentage of the combined AGI.

What is included in "gross income" under Virginia child support law?

Virginia defines gross income very broadly as "all income from all sources" under Va. Code § 20-108.2(C). It includes salaries, wages, commissions, royalties, bonuses, severance pay, dividends, interest, trust income, annuities, capital gains, pensions, retirement benefits, Social Security (both retirement and disability, including derivative child benefits paid to the parent), workers' compensation, unemployment insurance, disability insurance, and income from self-employment (net of reasonable business expenses). Means-tested public assistance benefits like TANF and federal SSI are excluded. Income from second jobs is excluded only if the job was obtained specifically to pay down an existing child support arrearage.

What is the 90-day threshold for shared custody in Virginia?

Under Va. Code § 20-108.2(G), Virginia uses different calculation methods based on the number of days each parent has the child. Sole Custody calculation applies when one parent has the child for fewer than 90 days per year (the other parent has 276+ days). Shared Custody calculation applies when each parent has custody or visitation of the child for 90 or more days per year. This is a critical legal threshold: shifting from 89 to 90 days changes the entire calculation methodology from a simple pro-rata model to a more complex cross-credit formula that multiplies the Basic Obligation by 1.5 to account for dual household costs and then offsets each parent's theoretical obligation based on custody time. This can result in significant and abrupt changes in the support amount.

How does Virginia handle split custody child support?

Split custody applies when there are two or more children and each parent has primary physical custody of at least one child. Virginia uses Form DC-638 for this scenario. The calculation involves running two separate Sole Custody calculations: one for the child(ren) living with Parent A (where Parent B is the non-custodial parent), and another for the child(ren) living with Parent B (where Parent A is the non-custodial parent). The final child support order is the net difference between the two calculated amounts, with the parent having the higher obligation paying the net amount to the other parent.

Virginia Child Support Formula 2025 | Income Shares Model Explained

Legal Standard

Virginia child support calculations under Va. Code § 20-108.2 establish a rebuttable presumption that the guideline amount is correct. Courts retain discretion to deviate if applying the guidelines would be "unjust or inappropriate" based on the specific circumstances of the case.

The Income Shares Model

Virginia employs the Income Shares Model for calculating child support. The foundational principle is that a child should receive the same proportion of parental income as they would have received if the parents lived together in an intact household.

Under Va. Code § 20-108.2, the calculation involves:

Determining each parent's Adjusted Gross Income (AGI)
Combining both parents' AGIs
Looking up the Basic Child Support Obligation on the statutory schedule
Applying linear extrapolation for incomes between schedule rows
Adding mandatory health insurance and childcare costs
Prorating the total obligation based on each parent's income share

The schedule covers combined monthly gross income from $0 to $35,000. For incomes above the schedule, courts have discretion to apply the guideline percentages or other factors.

Step 1: Calculating Adjusted Gross Income (AGI)

Gross income is defined as "all income from all sources" under Va. Code § 20-108.2(C). It includes wages, salaries, bonuses, commissions, self-employment income, dividends, interest, capital gains, retirement benefits, Social Security, unemployment, workers' compensation, disability insurance, and trust income.

AGI Calculation Formula

AGI = Gross Income 
  − Spousal Support Paid 
  + Spousal Support Received 
  − Child Support for Other Children 
  − Business Expenses (self-employment) 
  − ½ Self-Employment Tax

Key Adjustments

Spousal Support: Subtract any court-ordered or written-agreement spousal support paid; add any spousal support received
Support for Other Children: Deduct actual child support paid under existing orders. For other biological/adopted children residing in the household (not under an order), deduct a theoretical support amount calculated using the parent's individual gross income and the schedule
Self-Employment: Deduct reasonable business expenses and one-half of self-employment tax

Important: Income from a second job is excluded only if that job was obtained specifically to pay down an existing child support arrearage. Social Security disability benefits paid directly to or for the child based on a parent's entitlement are included in that parent's gross income.

Step 2: Schedule Lookup & Linear Extrapolation

After calculating AGI for each parent, combine both AGIs to determine the Combined Monthly AGI. Use this amount and the number of children to look up the Basic Child Support Obligation on the statutory schedule in Va. Code § 20-108.2(B).

Linear Extrapolation Requirement

For combined income amounts falling between schedule rows, Virginia law requires linear extrapolation (interpolation). This is a critical mathematical operation that ensures precise calculation regardless of income level.

Extrapolation Formula

Let: 
I_low = Schedule income row below Combined AGI 
I_high = Schedule income row above Combined AGI 
O_low = Basic obligation for I_low 
O_high = Basic obligation for I_high 
I_actual = Parties' actual Combined AGI 

O_actual = O_low + [(I_actual − I_low) / (I_high − I_low)] × (O_high − O_low)

Example

Combined AGI: $3,250/month | Number of Children: 2

• Schedule row $3,000 (2 children): $602 obligation
• Schedule row $3,500 (2 children): $694 obligation
• Extrapolated: $602 + [($3,250−$3,000)/($3,500−$3,000)] × ($694−$602)
• Extrapolated: $602 + [0.5 × $92] = $602 + $46 = $648

Custody Arrangements: The Critical 90-Day Threshold

The most important conditional logic in Virginia child support calculation is the 90-day custody threshold under Va. Code § 20-108.2(G). This threshold determines which calculation methodology applies.

Sole Custody

Applies when: One parent has child for <90 days/year (other parent has 276+ days)

Worksheet: Virginia Form DC-637

Method: Simple pro-rata allocation. Non-custodial parent's share = (Total Obligation × NCP Income %). Adjust for direct payments of health insurance/childcare.

Shared Custody

Applies when: Each parent has child for ≥90 days/year

Worksheet: Virginia Form DC-640

Method: Complex cross-credit formula. Basic Obligation multiplied by 1.5 to account for dual household costs. Each parent's share prorated by custody time, then offset.

Critical Threshold Impact

Shifting parenting time from 89 to 90 days fundamentally changes the calculation methodology, not just the amount. This can result in significant and abrupt changes in the support obligation. Courts and parties must carefully document actual days spent with each parent.

Split Custody

Split Custody applies when there are two or more children and each parent has primary physical custody of at least one child. This triggers Virginia Form DC-638, which involves:

Run a full Sole Custody calculation for child(ren) with Parent A (Parent B is NCP)
Run a second Sole Custody calculation for child(ren) with Parent B (Parent A is NCP)
Offset the two obligations: Final Payment = |Payment_B→A − Payment_A→B|
The parent with the higher obligation pays the net amount

Step 3: Mandatory Add-On Expenses

The Basic Child Support Obligation covers core expenses like food, shelter, and clothing. Two categories of expenses are mandatory additions under Virginia law:

Health Insurance Premiums

Legal Authority: Va. Code § 20-108.2(E)

Add the monthly cost of health care coverage for the children only (medical, dental, vision). If a family plan covers the parent and/or other children, the cost must be prorated to reflect the children-only portion.

Proration Method: Subtract the cost of individual coverage for the policyholder from the total cost, then divide the remainder by the number of remaining covered persons.

Work-Related Childcare Costs

Legal Authority: Va. Code § 20-108.2(F)

Add the actual monthly costs for childcare incurred by a parent due to their employment. The costs must be reasonable and necessary for the parent's employment.

Courts may require that care be provided by a licensed provider if requested by a party.

Total Support Obligation Formula

Total Obligation = Basic Obligation 
  + Children's Health Insurance Cost 
  + Work-Related Childcare Cost

Step 4: Prorating the Obligation

After determining the Total Support Obligation, each parent's share is calculated based on their percentage of the Combined Monthly AGI.

For Sole Custody

Parent A Income % = Parent A AGI / Combined AGI 
Parent B Income % = Parent B AGI / Combined AGI 

NCP Presumptive Support = Total Obligation × NCP Income % 
Final Payment = Presumptive Support − (NCP-Paid Health Insurance) − (NCP-Paid Childcare)

For Shared Custody

Total Shared Support = Basic Obligation × 1.5 
Parent A Share = Total Shared Support × Parent A Income % 
Parent B Share = Total Shared Support × Parent B Income % 

Parent A Custody % = Days with A / 365 
Parent B Custody % = Days with B / 365 

Parent A Owed = Parent A Share × Parent B Custody % 
Parent B Owed = Parent B Share × Parent A Custody % 

Initial Transfer = |Parent A Owed − Parent B Owed| 
(Adjust for direct health/childcare payments)

Virginia Child Support Formula: Income Shares Model Explained

Quick Facts