How much is self-employment tax in South Carolina?

The federal self-employment tax is 15.3% — 12.4% Social Security plus 2.9% Medicare — applied to 92.35% of your net earnings. South Carolina adds its own graduated income tax of up to 6.4% on the same net income, so the combined rate can exceed 20%.

What is the 92.35% factor in SE tax?

Self-employment tax is charged on 92.35% of net self-employment earnings, not the full amount. This adjustment approximates the employer-share FICA that a regular employee would not pay tax on, since self-employed people cover both halves themselves.

Can I deduct half of my self-employment tax?

Yes. You may deduct one-half of your self-employment tax when figuring your federal adjusted gross income. This calculator applies that deduction before estimating South Carolina state income tax, which lowers the state portion.

Does the Social Security wage cap apply?

Yes. The 12.4% Social Security portion of SE tax applies only up to the annual wage base ($168,600 for 2024); earnings above that pay only the 2.9% Medicare portion, plus a 0.9% additional Medicare tax on high earners.

South Carolina Self-Employment Tax Calculator

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If you are self-employed in South Carolina you owe both the federal self-employment tax and South Carolina state income tax on your net earnings. This calculator runs the full Schedule SE math, applies the deductible half-SE adjustment, and adds the state tax for a combined estimate.

How it works

Self-employment tax covers both the employee and employer shares of Social Security and Medicare. The calculation is:

SE base   = net earnings x 0.9235
SS tax    = 12.4% of SE base, up to the $168,600 wage base
Medicare  = 2.9% of SE base (+0.9% over $200,000)
SE tax    = SS tax + Medicare
half deduction = SE tax / 2
SC tax    = SC brackets on (net earnings − half deduction − std deduction)

The 92.35% factor removes the notional employer-share FICA from the base. Half of the resulting SE tax is deductible against income, which reduces the South Carolina state tax computed on the remainder using the 2024 graduated brackets.

Example

A freelancer with $80,000 of net earnings has an SE base of $73,880. The 15.3% SE tax is about $11,304, of which roughly $5,652 is deductible. South Carolina then taxes the income net of that deduction and the standard deduction at the 0/3/6.4 percent brackets, adding a few thousand dollars in state tax for a combined burden well above the SE tax alone.

Notes

This is a simplified estimate. It does not model federal income tax (only the SE tax and SC state tax), the qualified business income deduction, estimated-payment timing, or SC-specific subtractions and credits. The Social Security wage base and brackets change yearly. Confirm with Schedule SE and the SC1040 instructions at irs.gov and dor.sc.gov.