Self-Employment Tax Calculator

How it is calculated

The tool first reduces your net self-employment earnings to the taxable base, base = net earnings × 0.9235, then applies the two components of the US-style 15.3% rate: Social Security = min(base, 184,500) × 12.4% and Medicare = base × 2.9%, with SE tax as their sum. The $184,500 is the 2026 Social Security wage base the tool uses; it starts to bite once the base passes that figure, at about $199,800 of net earnings, after which Social Security stays at $22,878.00 while Medicare keeps rising with no cap. Net earnings means business income in dollars after deductible business expenses, not gross revenue. The tool has no additional Medicare surtax for high earners and no deduction for half of the tax. It covers self-employment tax only, not income tax, and other countries use different systems. Zero gives zero; negative or empty input returns no result.

Common mistakes

• Entering gross revenue instead of net earnings. The tax should be estimated on profit after business expenses, so entering sales makes the result far too high.
• Expecting 15.3% of the number you typed. The rate is applied to 92.35% of net earnings, so the tax is about 14.1% of net earnings below the Social Security cap.
• Treating the result as your whole tax bill. It covers Social Security and Medicare only; income tax is separate and is not calculated here.
• Applying 15.3% to every dollar of a high income by hand. The 12.4% Social Security part stops at the $184,500 wage base, so the effective rate falls for high earners, while Medicare continues.
• Expecting the extra Medicare surtax some high earners owe, or the deduction for half of the tax. Neither is included here.