South Carolina Quarterly Estimated Taxes (2026)

Yes - self-employed workers in South Carolina generally need to consider quarterly estimated taxes at both the federal and state level. You pay the IRS four times a year (April 15, June 15, September 15, January 15), and South Carolina may expect state estimated payments on its own schedule. Quartli's free calculator intentionally does not compute state tax from a blended rate; personalized South Carolina liability depends on income, filing status, residency, deductions, credits, and local rules.

Example: freelancer earning $80,000 in South Carolina

A single filer with $80,000 of net self-employment income in 2026 (standard deduction and a Sec. 199A QBI estimate):

Federal self-employment tax	$11,304
Federal income tax	$5,344
Federal quarterly payment	$4,162

Federal figures computed with official 2026 IRS brackets (Rev. Proc. 2025-32). State tax is not included in this free example because South Carolina liability depends on state-specific rules.

2026 quarterly due dates

Quarter	Income period	Federal due date
Q1	Jan 1 - Mar 31, 2026	April 15, 2026
Q2	Apr 1 - May 31, 2026	June 15, 2026
Q3	Jun 1 - Aug 31, 2026	September 15, 2026
Q4	Sep 1 - Dec 31, 2026	January 15, 2027

CPA-prepared South Carolina estimate

A licensed CPA prepares your personalized South Carolina state estimate - actual brackets, deductions, and credits, delivered by email within 48 hours, for a one-time $29. Available at quartli.com.

Frequently asked questions

Does South Carolina require quarterly estimated tax payments?

Yes. If you're self-employed in South Carolina, you generally owe BOTH federal quarterly estimated taxes (to the IRS) and South Carolina state estimated taxes (to the state revenue agency). The federal due dates are April 15, June 15, September 15, and January 15.

What is the South Carolina income tax rate for 2026?

South Carolina uses its own state tax rules, brackets, deductions, and credits. Quartli's free calculator does not calculate exact state liability because a single blended rate can be misleading - the CPA-prepared estimate applies the South Carolina rules to your actual filing details.

When are quarterly estimated taxes due in South Carolina in 2026?

Federal deadlines apply everywhere: April 15, 2026 (Q1), June 15, 2026 (Q2), September 15, 2026 (Q3), and January 15, 2027 (Q4). Most states, including South Carolina, follow the same schedule for state estimated payments, but always confirm with the state revenue agency.

How do I calculate my quarterly taxes as a freelancer in South Carolina?

Start with the federal side: self-employment tax (15.3% on 92.35% of net earnings) plus federal income tax, divided into four payments. Quartli's free calculator does this instantly using official 2026 IRS figures. For the South Carolina state portion, Quartli offers a CPA-prepared state estimate for $29.

Reviewed by Lena Hanna, CPA · Last updated June 2026 · Federal figures per IRS Rev. Proc. 2025-32. State rules vary by filing status, residency, deductions, credits, and local taxes.