South Carolina tax deadlines in 2026: filing dates and estimated payments
Deadlines that fall in calendar 2026: the 2025 return and the 2026 estimated payments. Different year? See South Carolina 2025 →
South Carolina deadlines in 2026
| 2025 individual return due | April 15, 2026 |
|---|---|
| Extended filing deadline | October 15, 2026 |
| Payment due | April 15, 2026, extension or not |
| Final 2025 estimated payment | January 15, 2026 |
| 2026 estimated payments | April 15, 2026 · June 15, 2026 · September 15, 2026 · January 15, 2027 |
Conforms to the federal deadline.
South Carolina estimated tax payments in 2026
You must file a Declaration of Estimated Tax (SC1040ES) if you expect to owe an income tax liability of $100 or more with the filing of your SC1040.
| Q1 (2026 tax year) | April 15, 2026 |
|---|---|
| Q2 (2026 tax year) | June 15, 2026 |
| Q3 (2026 tax year) | September 15, 2026 |
| Q4 (2026 tax year) | January 15, 2027 |
| Voucher | SC1040ES, Individual Declaration of Estimated Tax |
| Underpayment safe harbor | A penalty may apply if you do not pay at least 90% of the total tax due; generally avoided by timely payments equal to 100% of the tax shown on the prior-year SC1040, or 110% of last year's tax if prior-year adjusted gross income exceeded $150,000. |
| Pay online | dor.sc.gov |
Instead of the January 15 payment you may file the SC1040 by February 1 and pay in full. Farmers and commercial fishermen may pay all estimated tax by January 15, 2027 or file and pay by March 1, 2027. Act 110 (2026) changed South Carolina to two brackets for 2026 returns; account for the April and June payments when computing the September 15, 2026 installment.
Source: dor.sc.gov, read September 3, 2026. “1st quarter: due April 15, 2026 • 2nd quarter: due June 15, 2026 • 3rd quarter: due September 15, 2026 • 4th quarter: due January 15, 2027”
All 51 jurisdictions in one table: state estimated tax payment dates for 2026.
South Carolina extensions
Every state's rule in one table: which states accept the federal extension in 2026.
| Does South Carolina accept the federal extension? | Yes. A federal extension is honored; no state form. |
|---|---|
| State extension form | Form SC4868 |
| Original due date | April 15, 2026 |
| Extended due date | October 15, 2026 |
| Payment | Still due April 15, 2026. The extension is to file, not to pay. The extension allows more time to file but not to pay; penalty and interest are charged on tax not paid by April 15. |
| How to get it | With a federal extension and no tax due, simply mark the Extension box on the SC1040 (a copy of the federal extension is accepted); if you owe, pay on MyDORWAY (which auto-submits the request) or file SC4868 with payment by April 15. |
Source: dor.sc.gov, read September 3, 2026. “If no Income Tax is due and you have been granted an extension of time to file a federal Income Tax return, we will accept a copy of the federal extension.”
Federal deadlines in 2026
| 2025 Form 1040 | April 15, 2026 · extension October 15, 2026 |
|---|---|
| 2025 S-corp (1120-S) & partnership (1065) | March 16, 2026 |
| 2025 C-corp (Form 1120) | April 15, 2026 |
| 2026 federal estimated payments (1040-ES) | April 15, 2026 · June 15, 2026 · September 15, 2026 · January 15, 2027 |
Source: IRS Publication 509 and Form 1040-ES instructions, irs.gov.
Frequently asked questions
When are South Carolina state taxes due in 2026?
Your 2025 South Carolina individual income tax return is due April 15, 2026. If that date falls on a weekend or legal holiday, the deadline moves to the next business day. An extension moves the filing deadline to October 15, 2026, but any tax owed is still due on the original date.
When are South Carolina estimated tax payments due in 2026?
South Carolina estimated payments for the 2026 tax year are due April 15, 2026, June 15, 2026, September 15, 2026, January 15, 2027. Use SC1040ES, Individual Declaration of Estimated Tax or pay online. The final installment for 2025 was due January 15, 2026.
Does South Carolina accept the federal extension?
Yes. A federal extension is honored; no state form. The state form is Form SC4868. The extended filing deadline is October 15, 2026, and tax is still due by April 15, 2026.
Does a South Carolina extension give me more time to pay?
No. An extension extends the time to file, not to pay. To avoid penalties and interest, pay what you expect to owe by April 15, 2026.
Dates are the statutory deadlines that fall in 2026 and move to the next business day when they land on a weekend or holiday. Each section links to the source it was checked against. Always confirm with the South Carolina tax agency or the IRS before relying on a date. This is general information, not tax advice.