How South Carolina Calculates Child Support

South Carolina uses the Income Shares model to determine child support obligations. This page explains the guidelines, formula, and key factors.

Model Type

Income Shares (S.C. Code Regs. 114-4710 to 114-4750)

South Carolina looks up a basic support obligation from the 786-row statutory schedule by combined gross income and number of children, then prorates it by each parent's income share. Shared-custody cases -- where the parent with less time reaches 110 overnights a year -- use a 1.5× cross-calculation, blended gradually with the sole-custody figure through 127 overnights.

Sources & Verification

Core formula verified; some gaps disclosed below

Guideline effective 2024-01-01 · last checked against the primary source 2026-08-26

Primary sources

S.C. Code Regs. 114-4710 to 114-4750 — Child Support Guidelines South Carolina Child Support Guidelines, 2024 Edition (DSS Booklet 2819, NOV 24)

What this calculator doesn't yet handle

The 786-row Schedule of Basic Child Support Obligations was extracted programmatically from the booklet PDF and independently cross-checked against a separately-published edition of the same booklet (a different PDF at a different URL) — both agree on all 786 rows byte-for-byte, and the schedule is fully monotone in both income and child count with zero violations. See docs/sc-ak-calculator-plan.md §A3.
The regulation's own prose for the graduated-band overnight factor (114-4730(A)(3)) describes a denominator of 18 (128 minus 110), but the official printed Worksheet C "Overnight factor" table is unambiguously consistent with a denominator of 19 for all 19 published values, and only /19 makes the graduated band join Worksheet C continuously at 128 overnights. This calculator implements the worksheet's /19, not the regulation prose's /18.
Worksheet C line 12's obligation formula, as computed by the printed worksheet ("8(F) − 11(F) = 12(F)"), differs from the regulation's own narrative description of the same step (114-4730(A)(2)), which describes multiplying by that parent's own time percentage rather than the other parent's. This calculator implements the worksheet's arithmetic, corroborated by Alaska Civil Rule 90.3(b)(1)(B)'s identical cross-credit structure in an independent jurisdiction.
114-4710(A)(10)'s instruction to "extrapolate upwardly" between schedule rows is read as linear interpolation (consistent with how Virginia's identically-worded "extrapolated" instruction is implemented); an alternative reading — rounding up to the next $50 row — is not implemented.
The self-support reserve mechanism (114-4720(A)(11)) is applied to the Worksheet A / graduated-band sole-custody calculation only. The regulation does not describe how, or whether, it applies to the full Worksheet C shared-custody worksheet, so it is not applied there.
The work-related child-care tax-credit adjustment (114-4720(A)(14)) is implemented as: when the primary residential parent's income exceeds the published threshold, the lesser of an entered actual credit and a .27-of-expenses simulation (capped at $68/$135); when income does not exceed the threshold and no actual credit is entered, no adjustment is applied. The regulation's text does not fully specify this case.
Split custody (Worksheet B) is not implemented — the calculator collects a single overnight split for all children.
The twelve enumerated deviation factors under 114-4710(B) (educational expenses, equitable distribution, consumer debts, more than 6 children, extraordinary visitation travel, mandatory retirement/union deductions, substantial income disparity, lump-sum/rehabilitative alimony, party agreements, and others) are not calculated, only disclosed.
Imputed/potential income for a voluntarily unemployed or underemployed parent, and imputed income on non-income-producing assets, are not calculated.
Self-employment income is collected as a single gross figure; the regulation's business-expense reconstruction and accelerated-depreciation add-back (114-4720(A)(4)) are not implemented.
Unreimbursed medical expenses above $250 per child per year (114-4720(A)(12)) are not collected as a calculator input or added to the computed support figure — the regulation describes this as a pro-rata division the parties handle directly, separate from the worksheet's own lines, rather than as a worksheet line item.