How to Pay Your South Carolina State Income Tax

Where and how to pay South Carolina income tax

South Carolina collects state income tax through the Department of Revenue. You can pay online through their website, by mail, by phone, or in person at a local SCDOR office. The online portal is the fastest route—payments post the same day if submitted before 11:59 p.m. Eastern time on the due date. Mail and phone payments take longer to process, so if you are close to a deadline, online is safer.

The due date for South Carolina income tax is the same as the federal deadline: April 15 in most years, though it shifts if that date falls on a weekend or holiday. If you file a federal extension, you get an automatic extension for South Carolina as well, moving your deadline to October 15. An extension delays the filing deadline but does not delay the payment deadline—taxes owed are still due by April 15, or you will owe interest and penalties on the unpaid amount.

Key Takeaways

• South Carolina income tax is due April 15 each year, the same date as federal tax, and you can pay online, by mail, by phone, or in person at a SCDOR office.
• Paying online through the SCDOR website is fastest and posts the same day if submitted before 11:59 p.m. Eastern time on the due date.
• If you miss the April 15 deadline, you owe interest at 8 percent per year plus a failure-to-pay penalty that starts at 0.5 percent of the unpaid tax per month.
• A federal tax extension gives you until October 15 to file, but taxes owed are still due April 15—filing late without paying on time costs you penalties even if you later file an extension.
• If you cannot pay in full by the deadline, you can set up a payment plan with SCDOR, which allows you to pay over time but still charges interest on the unpaid balance.

Online payment through the SCDOR website

The South Carolina Department of Revenue operates an online payment system where you can pay by bank account (ACH transfer) or credit or debit card. To pay online, go to the SCDOR website, select the payment option, and enter your Social Security number or federal employer identification number, the tax year, and the amount owed. You will receive a confirmation number immediately.

ACH payments (direct bank transfer) are free and post the same day if submitted before 11:59 p.m. Eastern time. Credit and debit card payments charge a convenience fee—typically 2 to 3 percent of the payment amount—and the fee is added to your bill, not deducted from your payment. If you use a card, the payment still posts the same day, but the fee means you are paying more than you owe in tax alone.

Mail and phone payment options

You can mail a check or money order to the South Carolina Department of Revenue at the address listed on your tax notice or on the SCDOR website. Include your Social Security number, the tax year, and the amount on the check. Mail payments take 7 to 10 business days to post after they arrive, so if you are mailing close to the April 15 deadline, your payment may not post in time to avoid a late penalty, even if you mailed it before the deadline.

Phone payments are also available through the SCDOR automated system or by speaking with a representative. Phone payments charge a convenience fee similar to credit card payments online. The fee is added to your bill. Like mail payments, phone payments take several business days to post, so they are not the best choice if you are near the deadline.

What happens if you miss the April 15 deadline

If your payment does not post by April 15, South Carolina charges interest and penalties on the unpaid amount. Interest accrues at 8 percent per year, calculated daily. The failure-to-pay penalty starts at 0.5 percent of the unpaid tax per month (or part of a month) and can reach a maximum of 25 percent if the debt remains unpaid for a long time.

These penalties and interest are separate from the tax itself, so they increase what you owe. A $1,000 tax bill that sits unpaid for one year will cost you roughly $80 in interest plus at least $60 in penalties—nearly 14 percent more than the original amount. The longer you wait, the more the debt grows.

If you filed a federal extension but did not pay by April 15, you still owe the penalties and interest on the unpaid South Carolina tax. The extension covers the filing deadline, not the payment deadline. The only way to avoid the failure-to-pay penalty is to pay by April 15, even if you have not yet filed your return.

Setting up a payment plan if you cannot pay in full

If you cannot pay the full amount by April 15, you can contact the South Carolina Department of Revenue to set up a payment plan. A payment plan allows you to pay the tax over time in installments. You will still owe interest on the unpaid balance, and you may owe a setup fee for the plan itself, but the failure-to-pay penalty may be reduced or suspended while you are making on-time payments.

To set up a plan, call the SCDOR or visit an office in person. You will need to provide information about your income and expenses so the department can determine what you can afford to pay each month. Plans typically run from a few months to several years, depending on the amount owed and your ability to pay. Missing a payment on the plan can result in the plan being cancelled and the full amount becoming due immediately.

Estimated tax payments for self-employed and business owners

If you are self-employed or own a business, you may owe estimated tax payments to South Carolina in addition to your annual return. Estimated payments are made four times per year—usually in April, June, September, and January—and cover the tax on income you earn throughout the year that has no withholding.

Estimated payments are due on the 15th of the month (or the next business day if the 15th falls on a weekend). You can pay estimated taxes online through the SCDOR website the same way you pay your annual tax. If you do not make estimated payments and owe more than $500 when you file your annual return, you may owe an underpayment penalty in addition to the tax and interest.

Frequently Asked Questions

Can I pay my South Carolina tax with a credit card without a fee?

No. Credit and debit card payments through the SCDOR website charge a convenience fee of 2 to 3 percent, added to your bill. ACH payments (direct bank transfer) are free and post the same day. If you want to avoid the fee, use ACH instead.

What if I pay online but the payment does not post by April 15?

If you submit an online payment before 11:59 p.m. Eastern time on April 15, it posts the same day and you are on time. If you submit it after 11:59 p.m., it posts the next business day and you owe late penalties. Mail and phone payments take longer, so they are riskier near the deadline.

Do I have to file my return by April 15 if I cannot pay?

No. You can file your return and request an extension to October 15 without paying by April 15. However, taxes owed are still due April 15—filing late does not extend the payment deadline. You will owe interest and penalties on any unpaid tax, even if you later file an extension.

What is the difference between a federal extension and a South Carolina extension?

A federal extension automatically gives you a South Carolina extension as well. Both move the filing deadline to October 15. Neither one extends the payment deadline—taxes owed are due April 15 in both cases. If you do not pay by April 15, you owe penalties and interest on both your federal and South Carolina taxes.

Can I set up a payment plan if I owe less than $500?

Yes. South Carolina allows payment plans for any amount owed. However, you will still owe interest on the unpaid balance and may owe a setup fee. For small amounts, paying in full by the deadline is usually cheaper than setting up a plan.