Someone has handed you a number. Maybe it came from the other parent’s lawyer, maybe from a DSS caseworker, maybe from an online calculator at midnight. It looks either far too high or far too low, and nobody has explained where it came from. Understanding how child support is calculated in South Carolina is the first step to knowing whether that number is right, and whether your situation is one where the court can set a different one.

The formula: income shares

The South Carolina Child Support Guidelines, issued by the Department of Social Services and most recently revised in a 2024 edition that took effect January 15, 2024, describe the model in one sentence: it “calculates child support as the share of each parent’s income which would have been spent on the children if the parents and children were living in the same household.” The parent who does not have primary custody pays his or her share to the parent who does. The idea is that the child should receive the same proportion of parental income after the separation as before it.

The calculation runs in a fixed order. Each parent’s monthly gross income is determined. The two figures are combined and matched to a schedule in the Guidelines that sets a basic obligation for that combined income and that number of children. The cost of the children’s health insurance and of child care the custodial parent needs in order to work are added to the basic obligation. The total is then split between the parents by their percentage of the combined income. DSS publishes a calculator that runs the arithmetic, but the calculator is only as good as the numbers typed into it, and the numbers are where the disputes are.

What counts as income when child support is calculated in South Carolina

Almost everything. The Guidelines define gross income to include “income from any source including salaries, wages, commissions, royalties, bonuses, rents (less allowable business expenses), dividends, severance pay, pensions, interest, trust income, annuities, capital gains, Social Security benefits” and more. Overtime, a second job and self-employment income are in. So are disability benefits; our post on why VA disability counts as income for child support explains the most common surprise. What is excluded is narrow: means-tested public assistance such as TANF, SSI and food assistance.

Two rules catch parents who try to manage the number. First, income can be imputed. The Guidelines direct that if the court “finds that a parent is voluntarily unemployed or underemployed, it should calculate child support based on a determination of potential income,” meaning what that parent could earn given education, work history and the local job market. Quitting a job or taking a lower-paying one on the eve of a hearing does not lower support. Second, alimony and child support are linked: the Guidelines treat alimony paid or received as part of the income picture, which is why the South Carolina Supreme Court has held that child support must be recalculated when alimony is reversed.

The adjustments that change the number

• —Shared physical custody. The Guidelines apply a different worksheet where “each parent has court-ordered visitation with the children overnight for more than 109 overnights each year,” roughly thirty percent. Below that threshold the standard worksheet applies, and a schedule that gives one parent 100 overnights is calculated the same way as one that gives that parent every other weekend. This is the single adjustment that most often changes the result, and it is decided by the parenting plan, not by the support hearing.
• —Split custody. Where there are two or more children and each parent has primary custody of at least one, the Guidelines run a separate calculation for each household and offset the two.
• —Other children. Support a parent already pays under a court order for children of another relationship, and children living in the parent’s home, are taken into account before the number is set.
• —Health insurance and child care. The premium attributable to the children and the work-related child care cost, net of the tax credit, are added to the basic obligation and shared. Whoever pays them gets the credit on the worksheet, so the receipts matter.
• —The self-support reserve. The Guidelines build in a floor that protects a low-income paying parent’s ability to meet basic needs, so that support for the very lowest incomes is set below the strict formula.

When a judge can set a different number

S.C. Code § 63-17-470 makes the guideline amount “a rebuttable presumption” of the correct support. A judge may award a different amount “upon a showing that application of the guidelines in a particular case would be unjust or inappropriate,” but must then make “specific, written findings” that state what the guideline amount would have been and why the order differs. The statute lists the reasons a court considers, and they are worth reading against your own facts: educational expenses for the children, including private school; the equitable division of property; consumer debts; families with more than six children; extraordinary medical expenses of a parent or of a child; mandatory retirement and union deductions; support obligations for other dependents; fixed payments imposed by a court; significant income of the child; a substantial disparity where the paying parent earns much less than the receiving parent; alimony; and an agreement between the parents.

That last factor has its own rule. Parents may agree to a number that differs from the Guidelines, and the court may adopt it, but only where both are represented by counsel or the judge has examined an unrepresented parent to be sure the agreement is understood, and the court keeps “the discretion and the independent duty to determine if the amount is reasonable and in the best interest of the child.” An agreement that shortchanges the child can be rejected even when both parents signed it.

How the number is proved

Child support is decided on documents. Both parents file a sworn financial declaration required by Rule 20 of the Family Court Rules, and the worksheet is built from it: pay stubs, tax returns, business records for the self-employed, the insurance premium statement and the child care invoice. A parent who is being paid partly in cash, who runs income through a business, or whose bonus structure is irregular is the parent whose income becomes the contested question, and that question is answered with records, not with estimates. The same records support a later modification, because support can be changed when circumstances change substantially; the statute says that a change in the Guidelines alone is not such a change, except in a DSS case.

One more point that surprises people every year: the order is for money, paid through the court or the DSS system. Buying the children’s clothes or paying their activity fees directly, however generous, does not satisfy it. Our post on why direct payments do not count as child support explains why.

Frequently asked questions

Is the DSS calculator the final answer?

No. It runs the Guidelines arithmetic on the numbers you enter. The court decides what the numbers are, and whether any deviation factor applies.

Does 50/50 custody mean no child support?

Not automatically. Above 109 overnights each, the shared-custody worksheet applies, and it usually reduces support rather than eliminating it, because the parents’ incomes are rarely equal.

My ex quit a good job. Does support go down?

Not if the court finds the unemployment or underemployment is voluntary. Income is then imputed at what the parent could earn.

Can we agree on our own number?

You can propose one. The court can adopt it if both of you understand it, but it keeps the duty to decide whether the amount is reasonable for the child.

How long does child support last?

Until the child reaches the age and circumstances the law sets, with some exceptions for older children still in school. That deserves its own article, and it is the next post in this series.

Talk to a Charleston child support attorney

The formula is public. What is not obvious is which of your facts change it, and those are decided long before anyone runs the calculator. Klok Law handles family law matters across Charleston, Mount Pleasant, Berkeley and Dorchester counties. Call Klok Law at (843) 701-1695 to discuss your options.

This article is for general information only and is not legal advice. For advice about your specific situation, contact Klok Law at (843) 701-1695.