Free Self-Employment Tax Calculator (2026)
If you are a freelancer, contractor, or sole proprietor, self-employment tax is usually the biggest tax surprise of your first profitable year. There is no employer quietly paying half of your Social Security and Medicare — you pay both halves yourself. This free calculator estimates exactly what you owe for 2026: enter your net profit, and it shows the Social Security portion, the Medicare portion, any additional surtax, your deductible half, and what to set aside each quarter.
It runs entirely in your browser — nothing you type is stored or sent to a server. It estimates self-employment tax only, not your full income tax return.
What Is Self-Employment Tax?
Self-employment tax — formally SECA, the Self-Employment Contributions Act tax — funds Social Security and Medicare for people who work for themselves. The combined rate is 15.3%: 12.4% for Social Security and 2.9% for Medicare.
An employee pays only half of this (7.65% FICA) because their employer matches the other half. When you are self-employed you are both the employer and the employee, so you pay the full 15.3%. That is the entire reason contractors need to charge meaningfully more than an equivalent salary to end up in the same place.
You owe self-employment tax once your net earnings from self-employment reach $400 for the year. Below that, no SE tax is due — though you may still need to file a return for other reasons.
How Self-Employment Tax Is Calculated
The math has three steps, and the first one trips up most people.
- 1. Multiply your net profit by 92.35%. You do not pay SE tax on your full profit. The 7.65% reduction mirrors the employer-side payroll tax an employee would never be taxed on. The result is your “net earnings from self-employment.”
- 2. Apply 12.4% Social Security to those net earnings — but only up to the annual Social Security wage base ($184,500 for 2026). Earnings above that cap pay no more Social Security tax.
- 3. Apply 2.9% Medicare to all of your net earnings. Medicare has no ceiling. High earners also pay an extra 0.9% Medicare surtax above their filing-status threshold ($200,000 single, $250,000 married filing jointly).
Finally, you deduct one-half of your self-employment tax as an above-the-line adjustment, which lowers your adjusted gross income. Note that the 0.9% surtax is not deductible — this calculator handles that distinction correctly.
A Worked Example: $90,000 of Profit
Say you are a single freelancer with $90,000 of net profit and no other W-2 wages.
- Net earnings: 92.35% × $90,000 = $83,115.
- Social Security: 12.4% × $83,115 = $10,306 (well under the $184,500 cap).
- Medicare: 2.9% × $83,115 = $2,410.
- Surtax: $0 — earnings are below the $200,000 threshold.
Total self-employment tax: about $12,717, an effective rate of roughly 14.13% of profit (not 15.3%, thanks to the 92.35% factor). You deduct half — about $6,358 — from your adjusted gross income. And you would set aside roughly $3,179 per quarter for the SE tax portion of your estimated payments.
How Other W-2 Wages Change the Math
If you also hold a regular job, the Social Security tax already withheld from those wages uses up part of the annual wage base before your self-employment income is counted. Enter your W-2 wages in the calculator and it reduces the remaining Social Security-taxable amount accordingly.
If your W-2 wages already meet or exceed the wage base, your side business pays no additional Social Security tax at all — only the 2.9% Medicare (plus any surtax). This is why a high-salary employee with a freelance side income often owes far less SE tax than they expect.
Can You Legally Lower Self-Employment Tax?
Yes, within limits. The two most common levers are deducting every legitimate business expense — since SE tax applies to net profit, not gross revenue — and, at higher profit levels, electing S-Corp taxation so that only a reasonable salary is subject to payroll tax while distributions are not.
The S-Corp election is not free: it adds payroll, tax preparation, and bookkeeping costs, and the IRS requires a defensible reasonable salary. Use the S-Corp savings calculator linked below to see whether the savings clear those costs at your profit level. And remember that self-employment tax is separate from income tax — lowering one does not eliminate the other.
This tool provides estimates for planning purposes only and is not tax advice.