How is self-employment tax calculated?

Self-employment tax is 15.3% applied to 92.35% of your net self-employment earnings. That 15.3% is 12.4% for Social Security (only up to the annual wage base, $168,600 in 2024) and 2.9% for Medicare, which has no cap. You can deduct half of the SE tax when figuring income tax.

Does Mississippi charge extra self-employment tax?

No. Mississippi has no separate self-employment tax. Your self-employment profit is simply taxed as ordinary income at the state's near-flat 4.7% rate (2024), after the standard deduction, personal exemption, and the federal half-SE-tax deduction.

What is the 2024 Social Security wage base?

For 2024 the Social Security portion of self-employment tax (12.4%) applies only to the first $168,600 of combined wages and net self-employment earnings. Earnings above that are subject only to the 2.9% Medicare portion, plus a 0.9% additional Medicare tax at higher incomes.

Can I deduct half my self-employment tax?

Yes. The employer-equivalent half of your self-employment tax is an above-the-line deduction that reduces your adjusted gross income for both federal and Mississippi income tax. This calculator subtracts it before computing the Mississippi state tax.

Should I pay quarterly estimated taxes?

Usually yes. Self-employed people typically owe estimated taxes four times a year to both the IRS and Mississippi to avoid underpayment penalties. Use this estimate to budget your federal SE tax plus Mississippi income tax across quarterly payments.

Mississippi Self-Employment Tax Calculator

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Self-employed Mississippians owe two taxes on their profit: the federal self-employment (SE) tax that funds Social Security and Medicare, and Mississippi state income tax on the same earnings. This calculator computes both, including the deductible half of the SE tax.

How it works

Federal SE tax is applied to 92.35 percent of your net self-employment income (the portion that mirrors the employer/employee split):

SE base = net profit × 0.9235
SS tax  = min(SE base, $168,600) × 0.124
Medicare = SE base × 0.029
SE tax  = SS tax + Medicare

Half of the SE tax is deductible above the line. Mississippi then taxes the remaining income at its near-flat 4.7 percent rate (0 percent on the first 10,000 dollars of taxable income):

MS taxable = net profit − half SE tax − deduction − exemption
MS tax     = max(0, MS taxable − 10000) × 0.047
total      = SE tax + MS tax

Example

On 60,000 dollars of net profit, the SE base is 55,410 dollars. SE tax is 55,410 × 15.3 percent = about 8,478 dollars, half of which (4,239) is deductible. Mississippi taxable income after the 2,300 standard deduction and 6,000 exemption is about 47,461; tax on the portion above 10,000 at 4.7 percent is roughly 1,760 dollars. Combined: about 10,238 dollars.

Notes

Estimate only, not tax advice. The Social Security wage base and rates are 2024 figures; the additional 0.9 percent Medicare surtax above 200,000 dollars is not modeled. Mississippi’s flat rate phases to 4.4 percent (2025) and 4.0 percent (2026). Confirm with Schedule SE and Form 80-105.