How to File a South Carolina Amended Tax Return

To file a South Carolina amended tax return, submit a corrected SC1040 with the “Amended Return” box checked, attach Schedule AMD showing what changed and why, and mail the package to the South Carolina Department of Revenue. If the amendment is triggered by an IRS change to your federal return, you have 180 days from the IRS’s final determination to file with the state.¹

When You Need to Amend

South Carolina income tax begins with your federal taxable income, so any IRS adjustment to your Form 1040 flows into your state return. When the IRS finalizes a change, state law requires you to notify the SC DOR in writing within 180 days, and an amended state return is how you do that.¹

You should also amend when you find errors yourself. Common reasons include:

A corrected W-2 or 1099 that changes your federal adjusted gross income.
A missed state credit, such as the child and dependent care credit equal to 7% of the federal credit.²
The wrong filing status or a missing dependent.
A federal Form 1040-X you filed voluntarily that changes your South Carolina taxable income.

One boundary worth naming: not every federal change requires a state amendment. If the adjustment doesn’t affect your South Carolina taxable income or credits, there is nothing to correct at the state level.

Filing Deadlines

The 180-Day Rule for IRS Adjustments

When the IRS makes a final determination that changes your federal taxable income, you have 180 days from that determination to file your amended South Carolina return. The rule cuts both ways. If the change means you owe more state tax, the SC DOR can assess it within 180 days of receiving your notice. If the change means the state owes you money, you can claim the refund within the same 180-day window, even if the normal refund deadline has already passed.¹

General Refund Deadline

If the amendment isn’t tied to an IRS change and you’re seeking a refund, you must file within three years from the date the original return was filed (including extensions), or within two years from the date the tax was actually paid, whichever falls later.³ Miss both, and the refund is gone. The recoverable amount is also capped: a claim filed within the three-year period can’t exceed the tax you paid during the three years (plus extensions) before filing the claim.¹

If the amendment produces additional tax owed rather than a refund, no filing deadline protects you from paying. The SC DOR generally has 36 months from the original filing date to assess additional tax, and that window extends when federal changes are involved.¹

Which Form to Use

The form depends on the tax year you’re fixing. For tax year 2019 and later, file a new SC1040 with the “Amended Return” box checked on the front page and attach Schedule AMD.⁴ Complete the SC1040 as it should have read originally, with every schedule and attachment that would have gone with it. For tax year 2018 and earlier, use the standalone Form SC1040X; don’t use the current SC1040 with the amended checkbox or Schedule AMD for those older years.⁵

Nonresidents and part-year residents follow the same process. File a corrected SC1040 with the Amended Return box checked and include both Schedule AMD and Schedule NR.

Filling Out Schedule AMD

Schedule AMD uses a three-column format. Column A shows the figures from your original return. Column B records the net increase or decrease for each line you’re changing. Column C shows the corrected figures, which are Column A adjusted by Column B. Every line where a number moved needs entries in all three columns.

The form has a section for your explanation. Reference the specific line numbers you adjusted and describe why. Vague reasons like “correcting errors” slow processing. If the amendment stems from a federal change, say so, and identify the federal lines that moved.

What to Attach

The corrected SC1040 in full, with every original schedule that applies.
Any corrected income documents: revised W-2s, corrected 1099s, updated source forms.
If a federal change triggered the amendment, a copy of your finalized Form 1040-X and its supporting schedules.
If the IRS initiated the change, the IRS notice showing the final determination.

Interest and Penalties on Additional Tax

If your amended return produces a balance due, interest and penalties accrue from the original due date of the return, not from the day you file the amendment. Calculate them yourself and include them with your payment.

South Carolina’s underpayment interest rate changes quarterly and compounds daily, so the balance grows faster the longer you wait. The SC DOR does not waive interest, even for a good reason.⁶

Two penalties can apply. The late filing penalty is 5% of the unpaid tax per month or partial month, capped at 25%. The late payment penalty is 0.5% per month, also capped at 25%. Both can run at the same time.⁷

Penalty waivers are possible if you can show reasonable cause: you exercised ordinary business care and still could not file or pay on time. The burden is on you.⁸ Even without reasonable cause, the SC DOR may grant a partial waiver based on your filing history, the complexity of the error, and other factors.

Where to Mail It

The SC DOR does not accept electronically filed amended individual income tax returns. Print, sign, and mail the entire package. The address depends on the outcome:

Refund or zero balance: SC1040 Processing Center, PO Box 101100, Columbia, SC 29211-0100.
Balance due: Taxable Processing Center, PO Box 101105, Columbia, SC 29211-0105.

Check the address on the current form instructions before mailing, since the SC DOR occasionally updates them. The wrong address can delay processing by weeks. If you owe, include payment for tax, interest, and penalties with the package.

Processing Time and Checking Status

Amended returns go through manual review, which takes considerably longer than automated processing of original electronic returns. Expect at least 12 weeks from the date the SC DOR receives your amended return before a refund is issued.⁹ Complex adjustments or incomplete documentation stretch that further.

Track the return through the “Where’s My Refund?” tool on MyDORWAY. You’ll need your Social Security Number or ITIN and the exact refund amount from your amended filing.⁹

If the amendment is approved for a refund, it arrives by direct deposit (if you selected that) or by paper check. If the SC DOR determines you owe more, you’ll receive a notice with the corrected amount, interest, and penalties. Pay by the date on the notice to avoid further collection action.

If You Can’t Pay in Full

If the amendment creates a balance you can’t pay at once, the SC DOR offers payment plan agreements ranging from 12 to 48 months depending on the total owed, and you can request one through MyDORWAY.¹⁰ Interest and penalties keep accruing during the plan.

To qualify, you must stay current on all tax filings and estimated payments during the plan, provide a bank account for automatic drafts, and give the SC DOR any additional financial information it requests. Without bank drafts, you’ll need to pay 20% of the balance upfront.¹⁰ Missing any requirement lets the SC DOR move to collection immediately.

For debts of $10,000 or more (excluding penalties, interest, and court costs), an Offer in Compromise may let you settle for less, though the SC DOR considers these only when full collection is in doubt or economic hardship prevents payment.¹¹

1
South Carolina Legislature. South Carolina Code 12-54-85 – Time Limitation for Assessment of Taxes or Fees; Exceptions
2
South Carolina Legislature. South Carolina Code 12-6-3380 – Tax Credit for Child and Dependent Care Expenses
3
South Carolina Department of Revenue. SC Revenue Ruling 97-14 – Statute of Limitations for Claims for Refunds
4
South Carolina Department of Revenue. Amended Return Schedule
5
South Carolina Department of Revenue. 2019 SC1040 Individual Income Tax Form and Instructions
6
South Carolina Department of Revenue. SC Information Letter #26-9
7
South Carolina Legislature. South Carolina Code 12-54-43 – Civil Penalties and Damages
8
South Carolina Department of Revenue. Penalty Waiver (All Taxes)
9
South Carolina Department of Revenue. Refunds
10
South Carolina Department of Revenue. Payment Plan Agreements
11
South Carolina Department of Revenue. Offer in Compromise Information