Self-Employment Tax Calculator (US)
Estimate the US self-employment tax (Social Security and Medicare) you'll owe on your freelance profit, so quarterly taxes don't ambush you.
By Clemens AndritschkeUpdated
Business income minus business expenses.
Annual cap on the 12.4% Social Security portion. $184,500 for 2026 — change it if you are filing for a different year.
An extra 0.9% Medicare applies above this (about $200k single / $250k joint).
Estimate only — not tax advice
Estimated self-employment tax
$9,890.69
$4,945.34 of it is income-tax deductible
What self-employment tax actually is
When you're employed, you and your employer split Social Security and Medicare taxes. When you're self-employed you pay both halves yourself — that combined amount is self-employment (SE) tax, currently 15.3% (12.4% Social Security + 2.9% Medicare) on your net profit.
Two important details soften it: SE tax applies to 92.35% of your net profit, and you can deduct half of the SE tax when figuring your income tax. Social Security tax only applies up to an annual wage-base cap; Medicare has no cap and adds a small surtax at higher incomes.
Why estimate it now
Self-employment tax is separate from income tax and catches new freelancers off guard. In the US you generally pay estimated taxes quarterly, so knowing the figure early means you can set the money aside instead of scrambling at filing time. This calculator gives a planning estimate of the SE-tax portion; your total bill also includes federal and any state income tax.
Why it is 15.3% and why it hurts
Self-employment tax is Social Security and Medicare — the same contributions an employee makes, except an employee only ever sees half. The employer quietly pays the other half. When you go independent you become both parties, so you owe the full 12.4% for Social Security and 2.9% for Medicare: 15.3% in total.
This is separate from income tax and it is not optional above $400 of net earnings. It is also the number that catches people in their first year, because nothing was withheld along the way. A profitable first year and no quarterly payments is how a five-figure tax bill arrives as a surprise in April.
Two adjustments soften it. Only 92.35% of your net profit is subject to the tax, which roughly mirrors the employer-side deduction an employee never sees. And you can deduct half of the SE tax you owe from your taxable income for income-tax purposes — it does not reduce the SE tax itself, but it reduces the income tax stacked on top.
The cap that most calculators get wrong
Only the Social Security portion is capped. Once your combined wages and net earnings pass the annual wage base — $184,500 for 2026, up from $176,100 in 2025 — the 12.4% stops. The 2.9% Medicare portion never stops, and above $200,000 an extra 0.9% Medicare surtax begins.
That matters if you also hold a job. Wages from an employer count toward the same Social Security cap, so a freelancer with a $150,000 salary and $60,000 of side profit does not owe the full 12.4% on all of that profit — the salary has already used most of the cap. Enter the remaining headroom, not the full base, or you will overestimate badly.
The wage base is re-announced every autumn, which is why it is an editable field here rather than a constant baked into the code. If you are filing for an earlier year, change it to that year's figure.
$90,000 of net profit, 2026 rules
A consultant with no employer wages and $90,000 of net profit after expenses. He is well under the wage base and the surtax threshold, so both the cap and the surtax stay out of it.
| Step | Running figure | Why |
|---|---|---|
| Net profit | $90,000 | Revenue minus deductible business expenses |
| × 92.35% | $83,115 | The share of profit that SE tax applies to |
| Social Security 12.4% | $10,306 | Under the $184,500 cap, so the full amount is taxed |
| Medicare 2.9% | $2,410 | Uncapped, applies to every dollar of the base |
| Self-employment tax owed | ≈ $12,717 | |
That is before a single dollar of income tax. Half of it — about $6,358 — comes back as a deduction against taxable income, but the $12,717 itself is due. Setting aside 25–30% of profit as you earn it, rather than reaching for it in April, is the difference between a manageable bill and a payment plan.
Four ways this goes wrong
Assuming the 15.3% applies to revenue
It applies to net profit after business expenses, and then only to 92.35% of it. Calculating from revenue overstates the bill and makes the whole thing feel more hopeless than it is.
Forgetting employer wages count toward the cap
If you have a salaried job as well, those wages already consume part of the Social Security cap. Ignoring that overstates the 12.4% portion for anyone near the base.
Treating the deductible half as a refund
Deducting half of the SE tax lowers your taxable income, not your tax bill dollar for dollar. It is worth roughly your marginal income-tax rate on that amount, not the full half.
Waiting until April
SE tax is due as you earn it, through quarterly estimated payments. A large balance at filing time can carry an underpayment penalty on top of the tax.
Frequently asked questions
Is this my full tax bill?
What is the 92.35% adjustment?
What about the Social Security wage cap?
Is this tax advice?
Sources
- IRS — Self-employment tax (Social Security and Medicare taxes) — The 15.3% rate and its 12.4% / 2.9% split, the wage base, and the deductible half
- IRS — About Schedule SE (Form 1040), Self-Employment Tax — The form the tax is computed on, with the current-year form and instructions
- IRS — Estimated taxes — How and when to pay SE tax through the year
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