If you conducted business or earned income in South Carolina, you may be subject to South Carolina state taxes. If this applies to you, here are the key tax deadlines and extension details for South Carolina in 2024.
In South Carolina, you may:
File your taxes online for free via MyDORWAY
When filing by mail, ensure that your documents are postmarked by the due date.
Federal filing is required.
Amendments are allowed up to 3-years from the original date of filing.
Overview, Eligibility, and Limitations
Overview, Eligibility, and Limitations
Research and Development Tax Credit Program
The South Carolina Research & Development Tax Credit Program offers a tax credit for increasing qualifying research activities. It aligns with Internal Revenue Code Section 41 concerning qualified expenditures but calculates the credit solely on expenditures incurred within South Carolina.
5% of the qualified research expenditures that occurred in South Carolina
Taxpayers who claim a tax credit on their federal income tax for increasing research activities under IRC §41 are allowed a credit against corporate income tax equal to 5% of qualified research expenses made in South Carolina.
Eligible Entities
C-Corporations, S-Corporations, LLCs, Partnerships
Credit Carryforward
South Carolina allows a 10-year carry forward period for any unused credit.
The research credit is not refundable.
Credit Limitations
The R&D Tax Credit taken in any one taxable year cannot exceed 50% of a taxpayer's liability after all other credits have been applied.
S-Corporation / Partnership
You must file in South Carolina by March 15, 2025.
Applicable R&D Forms
Form SC-18 – Research Expenses Credit
File the above form with the following tax forms:
Form SC-1120S – South Carolina S-Corp Franchise or Income Tax Return
Form SC-1065 – Partnership Return of Income
Extension to File Taxes in South Carolina for 2024
Taxes owed in South Carolina for the tax year 2024 must be paid by March 15, 2025.
No separate extension filing is required in South Carolina.
South Carolina automatically grants a 6-month extension for both S-Corporation and Partnership tax returns.
S-Corporation: the extension deadline is September 15, 2025.
Partnership: the extension deadline is October 17, 2025.
Note that this extension pertains to the filing deadline, not the payment deadline.
Payment of taxes owed is still due by March 15, 2025.
C-Corporation
You must file in South Carolina by April 15, 2025.
Applicable R&D Forms
Form SC-18 – Research Expenses Credit
File the above form with the following tax forms:
Form SC-1120 – South Carolina C-Corporation Income Tax Return
Extension to File Taxes in South Carolina for 2024
Taxes owed in South Carolina for the tax year 2024 must be paid by April 15, 2025.
No separate extension filing is required in South Carolina.
South Carolina automatically grants an extension for C-Corporation tax returns.
C-Corporation: the extension deadline is October 15, 2025.
Note that this extension pertains to the filing deadline, not the payment deadline.
Payment of taxes owed is still required by April 15, 2025.
Sole-Proprietorship
Sole-Proprietorship
You must file in South Carolina by April 15, 2025.
Applicable R&D Forms
Form SC-18 – Research Expenses Credit
File the above form with the following tax forms:
Form SC-1040 – South Carolina Individual Income Tax Return
Extension to File Taxes in South Carolina for 2024
Taxes owed in South Carolina for the tax year 2024 must be paid by April 15, 2025.
No separate extension filing is required in South Carolina.
South Carolina automatically grants a 6-month extension for individual tax returns.
Sole-Proprietorship: the extension deadline is September 15, 2025.
Note that this extension pertains to the filing deadline, not the payment deadline.
Payment of taxes owed is still due by April 15, 2025.
References
We strive to ensure the accuracy of the information on this page, but it is not intended as investment, tax, or legal advice. Please use your own professional judgment and consult with a tax professional. Any advice you provide in connection with tax return preparation must comply in full with the requirements of IRS Circular 230.