Self-Employment Tax Explained: Why Freelancers Owe 15.3%
The first time a freelancer sees "self-employment tax" on their return, it usually comes as a shock: an extra 15.3% on top of regular income tax, on money they already thought of as theirs. It feels like a penalty for working independently. It is not — it is simply how the self-employed pay into Social Security and Medicare. Here is exactly what it is, why it is 15.3%, and the two rules that make the real cost lower than that headline number.
What self-employment tax actually is
Self-employment (SE) tax is your contribution to two federal programs:
- Social Security — 12.4%
- Medicare — 2.9%
Together that is 15.3%. When you are a W-2 employee, you pay half (7.65%) and your employer quietly pays the other half. Most people never notice it. The moment you go independent, you become both the worker and the employer — so you owe both halves yourself. That is the entire reason the number feels so large: you are seeing a cost that was always there, just previously hidden in an employer's books. (Source: IRS Self-Employment Tax.)
Two rules that lower the real cost
The 15.3% is not applied the way most people assume. Two adjustments bring the effective cost down:
- Only 92.35% of your profit counts. SE tax applies to your net profit multiplied by 0.9235, not the full amount. This roughly mirrors the fact that employers do not pay payroll tax on their own share.
- You deduct half of it. One-half of your SE tax comes off your income before income tax is calculated. So the employer-half you pay is not also hit by income tax — you are not taxed twice on it.
The caps and the extra tax at the top
Two more details matter as your income grows:
- Social Security has a ceiling. The 12.4% portion only applies up to the annual Social Security wage base, which is $184,500 for 2026 (SSA). Profit above that is not subject to the Social Security part — but the 2.9% Medicare portion has no cap and applies to every dollar.
- High earners pay a bit more. An extra 0.9% Additional Medicare Tax applies to earnings above $200,000 (single or head of household), $250,000 (married filing jointly), or $125,000 (married filing separately). Those thresholds are set by statute and are not adjusted for inflation.
A worked example
Say you are a single freelancer with $60,000 of net profit. SE tax applies to $60,000 × 0.9235 = $55,410. Of that, 12.4% goes to Social Security and 2.9% to Medicare — about $8,478 in SE tax total. You then deduct roughly $4,239 (half of it) before income tax is figured. Add federal income tax on top, and you can see why a "set aside 25–30%" habit exists.
Self-employment tax is not optional and it is not a trap — it is the same Social Security and Medicare everyone pays, just visible for the first time. Once you understand the 92.35% factor, the half-deduction, and the caps, the 15.3% becomes predictable, and predictable is exactly what you want at tax time. Plan for it, set money aside, and pay it in quarterly installments.
This is general educational information, not tax advice. Your situation may differ — confirm with a qualified tax professional before you file or pay.
Frequently asked questions
What is self-employment tax?
Self-employment tax is how the self-employed pay into Social Security (12.4%) and Medicare (2.9%), for a combined 15.3%. A W-2 employee splits this with an employer; when you work for yourself you pay both halves on your net earnings.
Why is self-employment tax 15.3%?
It combines the 12.4% Social Security rate and the 2.9% Medicare rate that normally are shared between an employee and employer. As your own employer you owe both shares. It applies to 92.35% of your net profit, and you can deduct half of it before income tax.
Is there a cap on self-employment tax?
The 12.4% Social Security portion only applies up to the annual wage base — $184,500 for 2026. The 2.9% Medicare portion has no cap, and an extra 0.9% Additional Medicare Tax applies to earnings above $200,000 (single) or $250,000 (married filing jointly).