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Your blog postWhy South Carolina Tax Returns Are Showing Unexpected Add-Backs in 2025
Confused by a $750, $1,125, or $1,500 add-back on your South Carolina tax return? Here’s why it’s happening and what you should do before filing.
Jeffrey Morris, EA
2/8/20261 min read


Why South Carolina Tax Returns Are Showing Unexpected Add-Backs in 2025
If you’re filing a 2025 South Carolina tax return and noticing a higher state taxable income than expected, you’re not alone. Many taxpayers are seeing confusing add-backs, especially related to itemized deductions and the federal standard deduction.
Here’s what’s happening.
The Real Cause: Federal Law Changed, South Carolina Didn’t
In mid-2025, federal tax law changed under the One Big Beautiful Bill Act. These changes increased the standard deduction and modified certain itemized deduction rules.
South Carolina has not yet adopted those changes. Because of that, some deductions allowed on your federal return must be added back to your income on the South Carolina return.
Why You May See Two Add-Backs
Some taxpayers are seeing two different adjustments on their return.
This happens because two separate South Carolina rules are being applied at the same time.
Add-Back #1: SALT Adjustment
South Carolina law requires an add-back when you itemize deductions that include state and local taxes.
This add-back is generally the difference between your itemized deduction and the federal standard deduction.
Add-Back #2: Federal Non-Conformity for 2025
Because South Carolina hasn’t adopted the new federal deduction amounts, the increase in the federal standard deduction must be added back to income.
Common Line 1e Add-Back Amounts
On SC1040 line 1e, you may see:
Single or Married Filing Separate: $750
Head of Household: $1,125
Married Filing Joint: $1,500
These amounts represent the portion of the federal standard deduction increase that South Carolina does not currently recognize.
Should You File Your South Carolina Return Now?
You generally have two options.
Option 1:
File your federal return now and wait to file South Carolina.
Option 2:
File both now and amend the state return later if the law changes, or SC could make the corrections on their end.
Many taxpayers are choosing to file federal now and wait on the state return until the legislature decides whether to adopt the federal changes.
Need Help Reviewing Your Return?
If your numbers don’t look right, a quick review can usually pinpoint the issue in minutes.
Email: jeffmorristax@gmail.com
