South Carolina estimated tax (quarterly) calculator

Plan quarterly payments based on South Carolina tax rules.

How this calculator works

Step 1 estimates your South Carolina tax based on the taxable income you provide and the bracket schedule (0% up to 6.2%). The tool adjusts for South Carolina-only income using your allocation %.

Step 2 uses your withholding and prior-year tax (if provided) to estimate a quarterly plan that aligns with South Carolina's 90% current-year or 100% prior-year safe-harbor rules.

Step 3 divides the remaining tax into four equal payments and lists the standard due dates used by South Carolina.

Frequently asked questions

When are South Carolina estimated payments due?

South Carolina uses the standard quarterly dates: April 15, June 15, September 15, and January 15 of the following year.

What if withholding changes later?

Recalculate with updated withholding to keep your quarterly plan accurate.

Is the safe harbor the same as federal?

South Carolina generally follows a 90% current-year or 100% prior-year safe harbor. Special rules apply if at least two-thirds of your income is from farming or ranching.

Estimates use South Carolina's published brackets and are not a substitute for official payment calculations.