The South Carolina Department of Revenue says taxpayers making estimated Income Tax payments should consult new guidance on legislative changes before their September 15 deadline.
COLUMBIA, S.C. — Taxpayers who must make South Carolina estimated Income Tax payments should review new state guidance before submitting their September 15 payment, according to the South Carolina Department of Revenue.
The agency published Information Letter #26-20 on Monday to explain how Act 110 of the 2026 legislative session affects Income Tax calculations for the 2026 tax year, according to the SCDOR. Returns for 2026 are not due until April 15, 2027, but the agency said taxpayers making estimated payments may need to adjust their September 15 payment based on the changes.
Act 110 creates two Individual Income Tax brackets with revised rates, according to the SCDOR. The law also decouples the state from certain federal deduction provisions, meaning South Carolina taxable income will now be calculated starting from federal adjusted gross income rather than federal taxable income, the agency said.
The law also establishes a new South Carolina Income Adjusted Deduction, which replaces the federal standard deduction and varies based on filing status and federal adjusted gross income, according to the SCDOR. The agency said it plans to launch a calculator for the new deduction on its MyDORWAY platform later this year.
Taxpayers who expect to owe $100 or more in state Income Tax must make estimated payments, according to the SCDOR. The agency directs taxpayers uncertain about their obligation to the 2026 Estimated Tax Worksheet included with the Individual Declaration of Estimated Tax form, known as the SC1040ES.
Payments can be made through the SCDOR’s MyDORWAY online system or by mailing the voucher included with the SC1040ES, the agency said.
The SCDOR noted that Act 110 does not affect 2025 Income Tax returns, which are due October 15, 2026, after the agency granted an automatic filing extension to all taxpayers in March.
Based on a release from S.C. Dept. of Revenue.
