South Carolina Business Tax Deadlines (2026)
Next: May 15 — Form 990 due for nonprofits
Next Deadline: May 15 — Form 990 due for nonprofits
Federal Tax Deadlines (2026)
| Form | Who Files | Due Date | Extension Deadline |
|---|---|---|---|
| Form 1040 (Schedule C) | Sole proprietors | April 15 | October 15 |
| Form 1065 | Partnerships, Multi-member LLCs | March 15 | September 15 |
| Form 1120-S | S-Corporations | March 15 | September 15 |
| Form 1120 | C-Corporations | April 15 | October 15 |
| Form 990 | Nonprofits | May 15 | November 15 |
| Estimated Taxes (Q1-Q4) | All | Apr 15, Jun 15, Sep 15, Jan 15 2027 | — |
South Carolina State Tax Deadlines (2026)
| Tax Type | Who Files | Due Date | Extension Deadline |
|---|---|---|---|
| Individual Income Tax (SC1040) | Individuals, sole proprietors | April 15 | October 15 |
| Estimated Income Tax (Q1-Q4) | Individuals owing $100+ | Apr 15, Jun 15, Sep 15, Jan 15 2027 | — |
| Corporate Income Tax (SC1120) | C-Corporations | April 15 (calendar year) | October 15 |
| S-Corp Return (SC1120-S) | S-Corporations | March 15 | September 15 |
| Partnership Return (SC1065) | Partnerships | March 15 | September 15 |
| Sales & Use Tax | Businesses with taxable sales | Monthly (20th) | — |
| Payroll — Employer Withholding | Employers | Quarterly or monthly | — |
| Business License Tax | Varies by municipality | Varies (typically April 15–May 1) | — |
| Annual Report | Corporations and LLCs | Anniversary of formation | — |
Quarterly Estimated Tax Deadlines in South Carolina
South Carolina follows the federal estimated tax schedule:
| Quarter | Due Date |
|---|---|
| Q1 | April 15 |
| Q2 | June 15 |
| Q3 | September 15 |
| Q4 | January 15, 2027 |
Estimated payments are required if you expect to owe $100 or more in SC income tax after withholding and credits. The threshold is notably lower than most states.
South Carolina-Specific Tax Requirements
South Carolina imposes a graduated individual income tax with rates being reformed under the Tax Cuts Act. For 2026, the state is transitioning toward a flat rate — the top rate is approximately 6.2% (down from the historical 7%), applying to income over $17,330. The rate is scheduled to continue decreasing. Business income from sole proprietorships and pass-through entities is reported on the individual SC1040 return.
The Corporate Income Tax is a flat 5% on net income apportioned to South Carolina — one of the lower corporate rates in the Southeast. There is no franchise tax, capital stock tax, or gross receipts tax at the state level, making SC's business tax structure relatively simple for corporations.
South Carolina's Sales and Use Tax has a state rate of 6%, with local option taxes of 1%–3% (combined rates up to 9% in some counties). Monthly returns are due by the 20th. A notable quirk is the Business License Tax imposed by most municipalities — this is a local gross receipts-based tax that varies significantly by city and industry classification. Some cities (Charleston, Columbia, Greenville) require annual business license renewals by April 15 or May 1. Employers must withhold state income tax and file quarterly or monthly depending on liability size.
What Happens If You Miss a South Carolina Tax Deadline?
South Carolina's late filing penalty is 5% of the tax due for each month (or fraction thereof) the return is late, up to a maximum of 25%. A late payment penalty of 0.5% per month of the unpaid balance also applies, up to 25%.
Interest on unpaid taxes accrues at the federal underpayment rate plus 2% — approximately 9%–10% per year for 2026. A negligence penalty of 5% of the total tax may be added if the underpayment is due to negligence or intentional disregard.
South Carolina grants a 6-month automatic extension if you have a valid federal extension or file SC4868 by April 15. However, you must pay at least 90% of the tax due by the original deadline. Sales tax returns and business license renewals cannot be extended.
South Carolina Department of Revenue
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