South Carolina Income Tax Calculator 2026

South Carolina income tax after Act 110

South Carolina income tax for 2026 is 1.99% of taxable income below $30,000. Once taxable income reaches $30,000, the whole amount is taxed at 5.21% and $966 is subtracted. The two formulas meet at $30,000, so there is no cliff, and the $966 adjustment means the 5.21% rate effectively applies only to income above the first bracket.

The $30,000 bracket amount is indexed each year to the Chained Consumer Price Index. The automatic rate cuts that start in 2027 follow a set formula: when the Board of Economic Advisors projects at least 5% growth in income tax revenue, the top rate is cut by enough to reduce collections by the greater of $200 million or 25% of the recurring income tax surplus (limited to the projected growth if that is smaller). Each cut is rounded up to the nearest hundredth of a percent, and the forecast in effect on February 15 decides the cut for that tax year.

Taxable income now starts from federal AGI

For 2026 and later, South Carolina no longer adopts the federal standard deduction or Schedule A itemized deductions. It also ignores the federal senior deduction, the qualified tip and overtime deductions, the car loan interest deduction, the qualified business income deduction and the charitable deduction for non-itemizers.

In their place is the South Carolina Income Adjusted Deduction (SCIAD), based on your federal filing status and reduced as AGI rises:

Worked example: single filer, $60,000 AGI

The reduction is the full deduction times (AGI − $40,000) ÷ $55,000, rounded down to the nearest $10. At $60,000 that is $15,000 × 20,000 ÷ 55,000 ≈ $5,450, leaving a SCIAD of $9,550.

Taxable income is $60,000 − $9,550 = $50,450. Because that is above $30,000, the tax is 5.21% × $50,450 − $966 = $1,662, an effective rate of 2.77% of AGI. Our calculator applies the full $15,000 deduction, so it would show less tax than this for anyone with AGI above $40,000.

Retirement income, Social Security and credits

Social Security and railroad retirement benefits that are taxed on your federal return are subtracted on the South Carolina return, so South Carolina does not tax them. On the 2025 SC1040, retirees could also deduct up to $3,000 of qualified retirement income if under 65, or up to $10,000 at 65 or older, with a separate military retirement deduction. Check the 2026 instructions when SCDOR publishes them.

The South Carolina earned income tax credit is 125% of the federal earned income credit but, starting in 2026, is capped at $200 a year. It is nonrefundable, so it can reduce your tax to zero but not below.

Who must file and when

Act 110 also changed the filing thresholds. For 2026 you must file if your South Carolina gross income is more than:

• $15,000 (single or married filing separately, under 65), or $30,000 if 65 or older
• $22,500 (head of household, under 65), or $37,500 if 65 or older
• $30,000 (married filing jointly, both under 65), $45,000 if one spouse is 65 or older, or $60,000 if both are
• Residents file Form SC1040. Nonresidents with South Carolina income file SC1040NR, and their SCIAD is reduced in proportion to South Carolina AGI over federal AGI. The normal due date is April 15, so 2026 returns are due April 15, 2027. SCDOR extended the deadline for 2025 returns to October 15, 2026.