Self-Employment Tax Calculator
Social Security and Medicare on business profit, including the deductible half.
Only 92.35% of profit is subject to the tax ($92,350 here), which stands in for the employer-half deduction an employee never sees. The rate is 15.3% because you are both employer and employee. Half of it is an above-the-line deduction against income tax, and this is on top of income tax rather than instead of it. 2026 figures.
Worked example. On $100,000 of net profit, only 92.35% is subject to the tax, so the base is $92,350. Social Security at 12.4% is $11,451 and Medicare at 2.9% is $2,678, a total of $14,130. Half of that, $7,065, is deductible against income tax. This is on top of income tax, not instead of it, which is what surprises people in their first year.
Frequently asked questions
Why 92.35% and not all of it?
It approximates the employer half of payroll tax, which an employee never counts as income. The adjustment keeps a self-employed person roughly level with an employee earning the same total.
Do W-2 wages reduce it?
They consume the Social Security wage base first. If a job already paid you up to the base, side income owes Medicare only, which can be a large difference. Enter your wages above to see it.
Does an S-corp election avoid this?
Partly. Paying yourself a reasonable salary and taking the rest as distributions can reduce the tax, but the salary must genuinely be reasonable, and the structure carries payroll filings and costs. It is worth modelling with an accountant rather than assuming.
What about quarterly payments?
Self-employment tax has no withholding, so it is paid through quarterly estimates. Missing them adds underpayment penalties even if you settle in full at filing.
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Calculators model hypothetical outcomes from the inputs you provide. They are informational only, not financial, investment, tax, or legal advice.