Self-Employment Tax Calculator
Self-employment tax is 15.3% — the Social Security and Medicare an employer would normally split with you. Enter your net business profit to see the 2026 figure, including the cap, the additional Medicare tax, and the half you get to deduct.
Where the 15.3% comes from
An employee pays 7.65% in payroll tax and the employer pays a matching 7.65%. Self-employed, you are both, so you pay the full 15.3% — 12.4% for Social Security and 2.9% for Medicare.
This is entirely separate from income tax. A freelancer at a 22% marginal income tax rate is looking at roughly 37% combined on the next dollar earned, which is why the first quarterly payment is such a shock.
The 92.35% adjustment
You do not pay SE tax on your full net profit. You pay it on 92.35% of it.
The reasoning: an employer deducts its half of payroll tax as a business expense, so the law gives the self-employed an equivalent adjustment before the tax is calculated. 92.35% is just 100% minus 7.65%.
On $80,000 of profit, that adjustment alone saves about $1,130.
The Social Security cap — and how W-2 wages interact
The 12.4% Social Security portion applies only up to the annual wage base, which is $184,500 for 2026 (up from $176,100 in 2025). The 2.9% Medicare portion has no cap and applies to every dollar.
If you also have a job, your W-2 wages fill the cap first. Someone earning $190,000 in salary pays no Social Security tax at all on their side business — only the 2.9% Medicare. This is why the calculator asks for W-2 wages, and why side-hustle tax estimates that ignore a day job can be badly wrong in the other direction.
An additional Medicare tax of 0.9% applies above $200,000 for single filers, $250,000 married filing jointly, and $125,000 married filing separately. These thresholds are set in statute and are not adjusted for inflation, so more people cross them every year.
The deduction is not a refund
You can deduct half of your self-employment tax from your gross income. It is an above-the-line deduction, available whether or not you itemise.
It reduces the income your income tax is calculated on — it does not reduce the SE tax itself, and it is not a credit. On a 22% bracket, a $5,500 deduction is worth about $1,200 in actual tax saved.
Note that the additional Medicare tax is excluded from the deductible half.
Quarterly payments
The quarterly figure here is self-employment tax only. Your income tax is on top of it, so your actual estimated payment will be considerably larger.
Payments are due in April, June, September, and January. Missing them triggers an underpayment penalty even if you settle the full balance in April. The common safe harbour is paying at least 100% of last year's total tax — 110% if your prior-year AGI was above $150,000 — which protects you from penalties regardless of how this year turns out.
This is an estimate, not tax advice. State taxes, the qualified business income deduction, retirement contributions, and health insurance deductions all change the final number. Confirm with a tax professional before making decisions.
Frequently asked questions
What is the self-employment tax rate for 2026?
15.3 percent — 12.4 percent for Social Security plus 2.9 percent for Medicare. It applies to 92.35 percent of your net business profit. The Social Security portion stops at $184,500 of combined wages and self-employment earnings for 2026; the Medicare portion has no cap.
Why is the tax calculated on 92.35% of my profit?
Because employers deduct their half of payroll tax as a business expense, and the law gives the self-employed an equivalent adjustment. Subtracting 7.65 percent before the tax is applied puts you roughly in the same position as an employee and their employer combined.
Do I still owe self-employment tax if I have a regular job?
You owe the Medicare portion on all self-employment earnings regardless. For Social Security, your W-2 wages count toward the $184,500 cap first, so if your salary already exceeds it you owe no Social Security tax on the business income. Enter your wages above to see the effect.
How much of the self-employment tax can I deduct?
Half, as an above-the-line deduction available whether or not you itemise. It lowers the income your income tax is figured on rather than reducing the SE tax itself, so its value equals half your SE tax multiplied by your marginal income tax rate. The additional 0.9 percent Medicare tax is not included in the deductible half.
When do I have to pay this?
Through quarterly estimated payments due in April, June, September, and January. Skipping them triggers an underpayment penalty even if you pay the full balance by the April deadline. Paying at least 100 percent of last year's total tax — 110 percent if your prior-year AGI exceeded $150,000 — is the usual safe harbour.