How is child support calculated in South Carolina?

South Carolina child support is governed by S.C. Code § 63-17-470 and the South Carolina Child Support Guidelines promulgated by the Department of Social Services (most recent comprehensive revision effective May 12, 2023).

1. Three Calculation Worksheets

Worksheet A — Sole Custody: Used when the noncustodial parent has fewer than 110 overnights per year.

Worksheet B — Shared Custody: Used when each parent has the child for at least 110 overnights (~30%) per year.

Worksheet C — Split Custody: Used when each parent has primary custody of at least one of the children.

2. Income Shares Calculation

Determine each parent's monthly gross income (wages, self-employment, dividends, pensions, Social Security, workers' comp, etc.).

Allowable adjustments: prior-order child support actually paid, court-ordered alimony to a former spouse, additional dependent deduction.

Combine adjusted gross incomes.

Find the Basic Child Support Obligation on the Schedule in the Guidelines (extends to combined adjusted gross of $40,000/month as of 2023).

Add work-related childcare, health/dental insurance premium for the child, extraordinary medical.

Pro rate by income share.

For Worksheet B, apply the shared-custody multiplier of 1.5 and offset.

3. Parenting Time Threshold

South Carolina is unusual in requiring 110 overnights (≈30%) — among the highest thresholds — before the shared-custody formula applies. Below 110, parenting time can still be a basis for deviation with written findings.

4. Self-Support Reserve / Minimum Order

The Guidelines protect the obligor's subsistence income. The minimum order is $100/month unless the court finds otherwise.

5. Duration (S.C. Code § 63-3-530(A)(17))

Support continues until the child:

Reaches age 18, OR

Graduates from high school (whichever later, if still enrolled), OR

May extend through college under Webb v. Sowell, 387 S.C. 328 (2010) — though Webb limited the family court's authority to order college support unless agreed by the parents in a marital settlement.

6. Modification (S.C. Code § 63-17-310)

Modification requires a substantial and material change in circumstances. Common qualifying changes: 20%+ income change, change in custody, change in child's needs, extraordinary medical expenses.

7. Imputed Income

Voluntary unemployment/underemployment allows imputation based on the parent's earning capacity considering work history, qualifications, and local labor market.

8. Deviation

Guideline amount is presumed correct; deviation requires specific written findings that application would be inappropriate. Common bases: extraordinary medical, very high or low income, special-needs child, agreed equal parenting time.

This is legal information, not legal advice.