South Carolina sales tax is filed online in MyDORWAY, the Department of Revenue's free tax portal, on Form ST-3, the State Sales and Use Tax Return. Returns are due the 20th of the month after the reporting period, and monthly filing is the default. You must file a return even when you have no tax due, and taxpayers with a South Carolina tax liability of $15,000 or more per filing period must file and pay electronically.
This guide covers who files and how often, how to file in MyDORWAY, how South Carolina's local taxes fit in, how to report no sales, how to amend a return, how to pay, the timely-filing discount, and what late filing costs.
This article is educational information, not tax advice. Filing rules, thresholds, and penalties can change, so confirm current requirements with the South Carolina Department of Revenue before you file.
South Carolina sales tax filing at a glance
- Who administers it: South Carolina Department of Revenue (SCDOR).
- Online portal: MyDORWAY, at MyDORWAY.dor.sc.gov.
- Return: Form ST-3, State Sales and Use Tax Return, with the ST-389 Schedule for Local Taxes where local tax applies.
- Filing frequency: Monthly by default. Quarterly and annual filing require SCDOR approval.
- Due dates: The 20th of the month after the reporting period. A due date on a Saturday, Sunday, or legal holiday moves to the next business day.
- Zero returns: Required every period, even if no tax is due.
- Electronic filing: Required when your South Carolina tax liability is $15,000 or more per filing period.
- Payment: ACH debit or major credit card in MyDORWAY.
- Timely-filing discount: 3% of the tax due if under $100, 2% if $100 or more, with annual caps.
- Economic nexus: $100,000 in sales into South Carolina in the previous or current calendar year.
Who has to file, and how often
If you have a South Carolina Retail License, you file an ST-3 to report sales and use tax. Anyone engaged in retail sales in South Carolina, including online sales, needs a Retail License. Remote sellers must get one when their sales of tangible personal property, products transferred electronically, or services delivered into South Carolina exceed $100,000 in the previous or current calendar year. Our South Carolina sales tax guide covers registration and nexus in more detail. Selling apparel? Our post on South Carolina sales tax on clothes explains how it is treated there.
Monthly is the default frequency for retailers. To file quarterly or annually you must request approval from SCDOR, through a MyDORWAY message or by email to SalesTax@dor.sc.gov.
| Frequency | Due date |
|---|---|
| Monthly (default) | The 20th of the month following the reporting month |
| Quarterly (with approval) | The 20th of the month following the end of the calendar quarter |
| Annual (with approval) | The 20th of the month following the end of the calendar year |
SCDOR's sales tax FAQ says that, generally, quarterly filing may be approved if total tax due (state and local) on a return does not exceed $100 for any month. It does not publish a dollar threshold for annual filing, so ask SCDOR. Businesses with two or more retail locations can apply for SCDOR's Consolidated Sales Tax Return program to file one return for all locations.
Before you start: your MyDORWAY account
You need a Retail License before you can file. It is applied for on MyDORWAY, and remote sellers pay a one-time $50 fee per retail location; our sales tax permit overview explains how registration works in general. MyDORWAY offers three access types: Individual, Tax Account Manager, and Business Owner. Signing up needs an identifier such as your FEIN or SSN plus verification details such as your last payment amount or line 1 from your last return, and Tax Account Managers and Business Owners also need the Business File Number. Passwords must be at least 14 characters.
Before filing, gather your records for the period: gross sales, exempt sales and other deductions, and deliveries into counties and municipalities with local taxes. SCDOR requires you to keep records that support every deduction you claim. For sales to resellers, see our South Carolina resale certificate guide for what to collect from buyers.
Step-by-step: filing Form ST-3 in MyDORWAY
- Log in to MyDORWAY. Select the Accounts tab and scroll to your Sales & Use Tax account.
- Click File a Return to start the ST-3 for the period.
- Enter gross proceeds. Report all sales, rentals, and withdrawals of inventory for your own use, plus out-of-state purchases subject to use tax. Do not include the sales tax you collected.
- Enter deductions. Claim exempt sales, sales for resale, out-of-state deliveries, and similar deductions, identifying the type and dollar amount of each.
- Complete the local tax schedule. The ST-389 is part of the same workflow in MyDORWAY.
- Review, claim any discount, and pay. MyDORWAY calculates amounts automatically. Submit and pay by the due date to keep the discount.
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Local tax pitfalls
The ST-3 applies the 6% state rate, and local taxes are reported separately on the ST-389. You must file the ST-389 when your business is located in a county that imposes a local tax, or when you deliver to a county or municipality with a local tax, whether or not your business is located there. So a seller with no South Carolina store can still owe local tax on deliveries into a taxing county.
Local rules also differ from state rules. SCDOR notes, for example, that unprepared food is exempt from state tax but local taxes still apply unless the local law exempts it, and that a state deduction is not automatically a local deduction. Our South Carolina sales tax calculator shows current rates by location.
Due dates and the weekend rule
Monthly returns are due on the 20th of the following month, so a January return is due February 20. Quarterly returns are due on the 20th of the month after the quarter ends, so the July through September quarter is due October 20. Under Code Section 12-60-50, when the due date falls on a Saturday, Sunday, or legal holiday, it moves to the next business day. For sales and use tax, SCDOR treats a legal holiday as any day the Department or the U.S. Postal Service is closed. Our South Carolina sales tax due dates page lists upcoming dates for every state.
Filing a zero return
You must file even when you had no sales. SCDOR's ST-3 instructions say to enter 0 on line 1 and line 3 if you have no sales or purchases to report, and its FAQ answers a question about periods with no sales with a plain yes. Filing on time also avoids the failure-to-file penalty, which is separate from the failure-to-pay penalty.
Amending a return
Use the same return form you normally file, the ST-3 or ST-389, and check the Amended Return box. MyDORWAY also lets you edit, delete, or amend a submitted business return. If you overpaid, you cannot take a credit on next month's return. SCDOR says to file a refund claim instead.
Payment methods
MyDORWAY accepts these payment methods:
- ACH debit or electronic funds withdrawal: Pay from your bank account, or schedule an ACH payment up to 45 days ahead for business taxes.
- Credit card: Visa, Mastercard, American Express, and Discover.
Pending ACH payments can be canceled in MyDORWAY, but credit card payments cannot. SCDOR also offers a paper ST-3, but taxpayers at or above the $15,000-per-period liability level must file and pay electronically.
The timely-filing discount
South Carolina lets you keep a discount for filing and paying in full by the due date. If the tax due on the return is under $100, the discount is 3%. If it is $100 or more, it is 2%. No discount is allowed when SCDOR receives either the return or the payment after the due date.
The discount is capped at $3,000 per state fiscal year, July 1 through June 30, or $3,100 for taxpayers who file electronically. The cap applies to the taxpayer, not to each location. A discount is not recomputed on an amended return filed after the original due date, and it is never required to be repaid because of an amendment.
Penalties and interest for late filing
- Failure to file: 5% of the amount due for each month or fraction of a month the return is late, up to 25% of the tax due.
- Failure to pay: 0.5% of the amount due for each month or fraction of a month the payment is late, up to 25% of the tax due.
- Interest: Assessed under Sections 6621 and 6622 of the Internal Revenue Code. Rates change quarterly and compound daily.
- Lost discount: A late return or payment forfeits the timely-filing discount.
- Penalty waivers: You can ask SCDOR to waive penalties in MyDORWAY, or by mail on Form C-530 with supporting documentation. Waivers are decided case by case. SCDOR does not waive interest.
SCDOR provides a penalty and interest calculator at dor.sc.gov/calculator.
Common mistakes to avoid
- Skipping zero returns. A return is due every period, even with no sales.
- Leaving off the ST-389. Deliveries into a county or municipality with a local tax require it, even without a South Carolina location.
- Paying after the 20th. A late return or payment forfeits the discount, and a return postmarked after the 20th is past due.
- Assuming a quarterly schedule. Monthly is the default, and quarterly or annual filing needs SCDOR approval.
- Ignoring nexus. Remote sellers can owe South Carolina tax after crossing $100,000 in sales into the state, without any physical presence.
More state filing guides
Filing in more than one state? These step-by-step guides cover the portals, due dates, and penalties in other states. See them all in our state-by-state guide to filing sales tax online.
- How to file North Carolina sales tax online
- How to file Georgia sales tax online
- How to file Tennessee sales tax online
Let Kintsugi file for you
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Frequently asked questions
How do I file South Carolina sales tax online?
Log in to MyDORWAY, select the Accounts tab, open your Sales & Use Tax account, and click File a Return. Complete the ST-3 and the local tax schedule, then pay.
What form do I use to file South Carolina sales tax?
Form ST-3, the State Sales and Use Tax Return, plus the ST-389 Schedule for Local Taxes when local tax applies.
When is South Carolina sales tax due?
The 20th of the month after the reporting period. If the 20th falls on a Saturday, Sunday, or legal holiday, the due date is the next business day.
Do I have to file if I had no sales?
Yes. File the ST-3 and enter 0 on line 1 and line 3.
How do I amend a South Carolina sales tax return?
Use the same form you normally file and check the Amended Return box, or amend the return in MyDORWAY.
What is the economic nexus threshold in South Carolina?
$100,000 in sales of tangible personal property, products transferred electronically, or services delivered into South Carolina in the previous or current calendar year.
What is the penalty for filing South Carolina sales tax late?
5% of the amount due per month, up to 25%, for failure to file, and 0.5% per month, up to 25%, for failure to pay, plus interest under the Internal Revenue Code.
Sources
Checked September 29, 2026.
- South Carolina Department of Revenue, Sales Tax
- South Carolina Department of Revenue, ST-3 Instructions
- South Carolina Department of Revenue, MyDORWAY
- South Carolina Department of Revenue, Remote Sellers
- South Carolina Department of Revenue, Consolidated Sales Tax Return
- South Carolina Department of Revenue, Penalty Waivers
- South Carolina Department of Revenue, SC Revenue Ruling #21-7, Discount for Timely Filed Returns
- South Carolina Department of Revenue, Sales and Use Tax Manual, Chapter 23 Frequently Asked Questions
