How 1099 Taxes Work in South Carolina
As an independent contractor, sole proprietor, or 1099-NEC recipient operating in South Carolina, you do not have an employer withholding taxes from your paychecks. Instead, you are responsible for calculating and remitting both federal self-employment taxes and applicable South Carolina state taxes.
1. Federal Self-Employment Tax (15.3%)
Under IRS Schedule SE (Form 1040), 1099 professionals pay 15.3% on 92.35% of net business profits:
- 12.4% Social Security Tax: Applies to net earnings up to the annual wage ceiling ($168,600 for 2026).
- 2.9% Medicare Tax: Applies to all net earnings without an upper limit. High earners above $200,000 (single) or $250,000 (married) are subject to an additional 0.9% Medicare surtax.
2. South Carolina State Income Tax Rules
South Carolina levies state income tax with rates topping at 6.4%. Estimated state tax payments must be filed directly with the South Carolina Department of Revenue to avoid local underpayment penalties.
3. Quarterly Estimated Payment Deadlines
To avoid IRS Form 2210 underpayment penalties, freelancers owing $1,000 or more in federal taxes must pay quarterly installments via EFTPS or Direct Pay on:
- Q1 Deadline: April 15
- Q2 Deadline: June 15
- Q3 Deadline: September 15
- Q4 Deadline: January 15 (following year)