South Carolina Personal Income Tax Extension – Federal Extension Required
South Carolina grants an automatic six-month extension for filing personal income tax returns to taxpayers who have secured a valid federal extension through IRS Form 4868. The South Carolina Department of Revenue aligns with the federal timeline, extending the state filing deadline to October 15, 2026. No separate South Carolina extension form is needed – attach your federal extension when filing your return – but at least 90% of your South Carolina tax must be paid by the original due date.
90% Payment Threshold by April 15
Pay at Least 90% of Your SC Tax Liability on Time
South Carolina’s extension covers filing only – not payment. To avoid a late-payment penalty, at least 90% of any South Carolina tax owed must be paid by the original return due date. Falling short of 90% triggers the failure-to-pay penalty even if you file by October 15. Use MyDORWAY to pay online.
Attach Federal Extension When Filing
Include Your IRS Approval with Your SC Return
When filing your South Carolina return by October 15, attach a copy of your federal Form 4868 or the IRS electronic acknowledgment. South Carolina’s automatic extension is tied to that federal approval – it’s your documentation that the extension is valid.
Pay at least 90% of SC tax by April 15: South Carolina’s 90% threshold is firm. Use
MyDORWAY at mydorway.dor.sc.gov to pay online and attach your federal extension when filing by October 15, 2026.
Using Form SC4868
Form SC4868 (Request for Extension of Time to File South Carolina Individual Income Tax Return) is the payment voucher used when mailing an extension payment. Online payments are accepted through MyDORWAY at mydorway.dor.sc.gov – Visa, MasterCard, and electronic funds withdrawal (ACH) are accepted. No paper form is needed when paying online.
Late Filing and Payment Penalties
South Carolina’s failure-to-file penalty is 5% of unpaid tax per month, capped at 25%. The failure-to-pay penalty is 0.5% per month, also capped at 25%. Both can run simultaneously on an unpaid balance – paying at least 90% by April 15 and filing by October 15 keeps both penalties at zero.
Best Practices
- ✓File IRS Form 4868 by April 15 – South Carolina’s extension requires federal approval.
- ✓Pay at least 90% of your South Carolina income tax by April 15, 2026, via MyDORWAY at mydorway.dor.sc.gov.
- ✓Attach a copy of your federal extension when filing your South Carolina return by October 15.
- ✓File your completed South Carolina return by October 15, 2026.
South Carolina’s 90% payment threshold is the key detail to track – unlike states that only require paying the balance in full or making no payment at all, SC sets a specific minimum. Secure your federal extension, pay at least 90% by April 15, attach the extension when you file, and submit by October 15, 2026.
Quick Reference Table
South Carolina State Tax Extension
