South Carolina (SC)
April 15, 2026
October 15, 2026
✓ Automatic w/ Federal
SC — South CarolinaSouth Carolina Personal Income Tax Extension — What You Need to Do
South Carolina automatically honors a federal extension (Form 4868) for the same length of time the IRS grants, or you can file Form SC4868 directly. Either way, at least 90% of your total SC tax liability must be paid by April 15, 2026 to avoid a penalty.
South Carolina Extension Checklist — 2026
Two things to handle. A federal extension is automatically honored, but the 90%-paid-by-April-15 rule applies regardless.
April 15, 2026
Pay At Least 90% of SC Tax Due
Pay Online via MyDORWAY
mydorway.dor.sc.gov
Paying online with a balance due can itself satisfy the extension request — no SC4868 needed.
Check with Form SC4868 SCDOR, IIT Voucher
PO Box 100123
Columbia, SC 29202
An extension doesn’t extend the time to pay — interest still accrues.
October 15, 2026
File Federal + South Carolina Return
File your federal return now and add your South Carolina state return — Form SC1040 for residents (SC1040NR for nonresidents/part-year) — in the same session. SCDOR’s blanket filing extension to October 15 applies whether or not you separately filed an extension.
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South Carolina Late Filing & Payment Penalties — What It Costs to Wait
South Carolina charges separate monthly penalties for late filing and late payment, compounded daily interest, and a minimum penalty if you’re more than 60 days late.
| Charge Type | Rate | Cap | Trigger |
|---|---|---|---|
| Late-Filing Penalty | 5% per month (or part-month) | 25% (min. lesser of $100 or 100% of tax if 60+ days late) | Return filed after October 15, 2026, or without a valid extension |
| Late-Payment Penalty | 0.5% per month (or part-month) | 25% of tax due | SC tax not paid by April 15, 2026 |
| Interest | 7% per year (compounded daily; Jul–Sep 2026 rate) | No cap | Accrues from April 15 on any unpaid balance |
South Carolina State Extension Details
| Extension Type | Automatic with Federal Extension (plus a 2026-only blanket filing extension) |
| Original Payment Deadline | April 15, 2026 (unchanged) |
| Extended Filing Deadline | October 15, 2026 |
| Extension Period | 6 months (federal-aligned); also a separate 2026-only blanket extension for all filers due to IRC conformity delay |
| Extension Form | Form SC4868 — optional if you have a federal extension |
| Return Form | Form SC1040 (residents); SC1040NR (nonresidents/part-year) |
| Federal Extension Required? | Not required — SCDOR automatically honors a federal extension for the same length; SC4868 is an alternative, not an additional requirement |
| Payment Deadline | At least 90% of total SC liability must be paid by April 15, 2026 |
| Online Payment Portal | MyDORWAY |
| Extension/SC4868 Payment Mailing Address | SCDOR, IIT Voucher, PO Box 100123, Columbia, SC 29202 |
| Return Mailing Address (refund/zero due) | SC1040 Processing Center, PO Box 101100, Columbia, SC 29211-0100 |
| Return Mailing Address (balance due) | Taxable Processing Center, PO Box 101105, Columbia, SC 29211-0105 |
| State Agency | South Carolina Department of Revenue |
| Late-Filing / Late-Payment Penalty & Interest | 5%/month late-filing (cap 25%); 0.5%/month late-payment (cap 25%); 7% interest compounded daily |
South Carolina Tax Extension — Frequently Asked Questions
Why is the SC filing deadline October 15 for everyone this year?
SCDOR announced a blanket filing-deadline extension to October 15, 2026 for all 2025 individual returns because of a delay in South Carolina’s conformity to recent federal tax law changes. This applies automatically, regardless of whether you separately requested an extension — but it did not change the April 15 payment deadline.
Do I need to file Form SC4868?
Not if you already have a federal extension — SCDOR automatically honors it for the same period. SC4868 is only useful if you want a standalone SC extension without a federal one.
What is the 90% rule?
At least 90% of your total SC tax liability must be paid by April 15, regardless of any filing extension. Falling short triggers the late-payment penalty on the shortfall.
What if I’m due a refund?
If you’re due a refund, no extension form or payment is required. Filing sooner still gets your refund to you faster.
Which South Carolina return form do I need?
Form SC1040 for full-year residents. Nonresidents and part-year residents use Form SC1040NR.
Where do I mail my return versus my extension payment?
SC4868 payments go to PO Box 100123. Refund/zero-due returns go to PO Box 101100, and balance-due returns go to PO Box 101105 — three different addresses, so double-check before mailing.
Ready to File? Start Federal + South Carolina
File your federal return and add South Carolina state in the same session. October 15 filing deadline — secure, fast, with live support.