Self-Employment Tax: The 15.3% Nobody Warns New Freelancers About (US)

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Educational only. This guide explains a system; it is not personal advice for your situation. Before you act on any tax or retirement figure here, consult a tax professional.

Short answer: This guide is about United States federal tax only. If you freelance in the US and your net self-employment earnings reach $400 or more in a year, you generally owe self-employment (SE) tax on top of income tax. For most freelancers below the Social Security wage base, that tax works out to 14.13% of net profit — not quite 15.3%, because it applies to 92.35% of profit, not to the full amount. It is the tax most new freelancers miss, and it is the reason a first April bill can be thousands higher than expected. Educational only — consult a tax professional for your situation.

Who this is for: You left a job, or started freelancing on the side, and your first tax bill was bigger than your income-tax maths suggested. Or you are about to file your first freelance year and want to see, step by step, where that extra tax comes from.

Who this is not for: If you are paid only through payroll withholding as an employee, you do not file Schedule SE for that pay. If you pay yourself a salary through a corporation, your mechanics are different. This guide is for sole-proprietor-style freelancers reporting on Schedule C.

Why an employee never sees this bill

When you were an employee, Social Security and Medicare taxes were split. You paid 7.65% — 6.2% Social Security plus 1.45% Medicare — and your employer paid the other 7.65%. The split happened before the money reached your bank account, so it never felt like a separate bill.

As a freelancer, there is no employer to pay the other half. You are both halves. So you pay the full 12.4% Social Security rate plus the full 2.9% Medicare rate: 15.3% combined. That is the whole shock, in one sentence. Nothing sneaky happened. The employer half just moved onto your return.

The chain, step by step

Take a fictional freelancer, Dana, a single copywriter who nets $60,000 in 2026 after deductible business expenses. Net profit here means freelance income minus deductible business expenses — the Schedule C figure — not the total of her 1099s. Here is the full chain:

Step 1 — Start with net profit: $60,000.

Step 2 — Multiply by 0.9235. The IRS taxes 92.35% of net profit for SE purposes. That 7.65% haircut is, in effect, the employer-half adjustment built into the maths.

$60,000 × 0.9235 = $55,410 of net earnings from self-employment.

Step 3 — Social Security at 12.4%, up to the wage base. For 2026 the Social Security wage base is $184,500. The 12.4% applies only to SE earnings up to that amount. Dana is well under it, so:

$55,410 × 0.124 = $6,870.84.

Step 4 — Medicare at 2.9%, with no cap. Medicare does not stop at the wage base:

$55,410 × 0.029 = $1,606.89.

Step 5 — Add them up.

$6,870.84 + $1,606.89 = $8,477.73 of SE tax.

Step 6 — Half of it is deductible for income tax. Dana subtracts half her Schedule SE tax — $8,477.73 ÷ 2 = $4,238.87 — when working out adjusted gross income. That half lowers her income tax. It does not lower her SE tax, and it is not a credit that comes back dollar for dollar. It just means the income-tax calculation starts from a smaller number.

That is the chain, every time: net profit → × 0.9235 → 12.4% to the wage base plus 2.9% uncapped → half deductible against income tax only.

What happens above the wage base

The Social Security part stops, but Medicare does not. A freelancer whose SE earnings pass $184,500 pays 12.4% only on the first $184,500 of SE earnings, then 2.9% Medicare on everything. That is why the effective SE rate falls at very high profits — the 12.4% slice stops growing while profit keeps growing.

There is one more layer at the top. An additional 0.9% Medicare tax applies to SE earnings above $200,000 for a single filer ($250,000 married filing jointly), reported on Form 8959. It is not part of Schedule SE tax, and it is not included in the deductible half. Most new freelancers will never meet it, but the banded table below shows it so the top row is honest rather than rounded away.

One coordination rule matters if you also have a job: W-2 wages count toward the $184,500 wage base first. If your employer already paid Social Security tax on $150,000 of wages, only $34,500 of SE-earnings room is left for the 12.4% slice on your freelance income. Schedule SE works that out, but a freelancer who applies 12.4% to all their freelance profit on top of a full W-2 year will overstate the bill.

Banded examples: the same maths at six profit levels

All rows are single-filer illustrations for 2026, before income tax, with no other income and no W-2 wages. The deductible half is half of Schedule SE tax only; the additional Medicare tax, where it appears, is excluded from that half.

Read the pattern in plain words. Up to the wage base, SE tax is a flat 14.13% of profit — 15.3% of 92.35%. At $200,000 of profit, SE earnings just cross the wage base, so the Social Security slice is capped at $22,878.00 and the rate dips slightly. At $250,000, Social Security has stopped growing entirely, Medicare keeps going, the small additional-Medicare slice appears, and the overall rate falls to 11.94% of profit. Higher profit does not mean a higher SE rate. It means the opposite, past the cap.

SE tax is not income tax

This is the confusion to clear up, because the two taxes sit on the same return and feel like one bill:

• SE tax is charged on 92.35% of net profit. The standard deduction does nothing to it. Retirement contributions do not lower it. The qualified business income deduction does not lower it. It is worked out first, on Schedule SE, and it is owed even in a year when income tax comes out low.
• Income tax is charged after you subtract half your SE tax, the standard deduction ($16,100 single for 2026), and anything else you qualify for, then run the result through the brackets. It can be small while SE tax is large, or large while SE tax has flattened past the wage base.

Two worked comparisons, single filer, 2026 standard deduction, no other income or credits:

At $40,000, SE tax is more than double the income tax. At $80,000, SE tax is still the larger half. A freelancer who budgets only for income tax is budgeting for the smaller tax and missing the bigger one. That is exactly the mistake the set-aside system in Guide B1 is built to prevent — see the hub at /tax/ and Guide B1, How Much of Each Payment Should a Freelancer Set Aside for Taxes?.

The $400 line, and what it does not mean

SE tax generally applies when net earnings from self-employment reach $400 in a year. Below that, no Schedule SE. That threshold is about SE tax only. It is not a "first $400 is tax-free income" rule, and it is not the same as the $2,000 figure for 2026 payments ($600 for 2025 payments) that governs whether a payer must send you a 1099-NEC — that contrast is covered in Guide B5. If you net $500 from a side project, the SE-tax maths applies to it even if no form ever arrives.

What this guide does not do

It does not describe ways to reduce SE tax, and it does not advise on changing business entity type. Those are professional-advice topics with their own costs, filing duties, and trade-offs, and a general educational guide is the wrong place to weigh them. If you are considering a change of structure, take the numbers in this guide to a tax professional and ask what that change would actually cost and save in your situation — consult a tax professional before acting on any figure here.

Checklist

• Your net profit figure is profit after expenses, not your 1099 total — see Guide B4, Freelancer Tax Deductions: What You Can Claim, What You Can't (US), for what counts as an expense.
• SE tax worked as profit × 0.9235, then 12.4% to the wage base plus 2.9% uncapped.
• Half of Schedule SE tax subtracted for income-tax purposes only — never from the SE tax itself.
• W-2 wages, if any, counted toward the wage base before freelance SE earnings.
• The SE figure fed into your set-aside rate (Guide B1) and your quarterly payments (Guide B2), not left for April.

What to do next

1. Work the SE-tax chain on your own net profit using the banded examples.
2. Run a payment through the tax set-aside calculator.
3. Consult a tax professional before you file on the basis of this guide.

Sources

• IRS Publication 334, Tax Guide for Small Business (who owes SE tax, Schedule C net profit, $400 net-earnings threshold).
• IRS Schedule SE and instructions (0.9235 multiplier; 12.4% Social Security and 2.9% Medicare rates; half-SE-tax deduction).
• Social Security Administration, 2026 wage base announcement ($184,500).
• IRS Form 8959 and instructions, Additional Medicare Tax (0.9% above the $200,000 single-filer / $250,000 joint threshold on SE earnings; additional tax excluded from the deductible half).
• IRS Revenue Procedure 2025-32 (2026 standard deduction of $16,100 single, used in the SE-vs-income-tax comparison).

Source links: IRS Publication 334 · Instructions for Schedule SE · IRS Additional Medicare Tax Q&A (explains Form 8959)

Dated assumptions: figures checked 25 Oct 2026; verify current-year limits before acting. Tax year 2026 throughout. Educational only. Consult a tax professional for your situation — this guide explains how SE tax is worked out; it does not decide what you owe.

Before you act: tax and retirement rules change, and your situation has details a guide cannot see. For any figure you plan to file, claim, or contribute on the basis of this page, consult a tax professional first.

Related guides and tools

• the tax hub
• how much of each payment to put aside for tax
• freelancer tax deductions: what you can claim, what you can't
• work out your own tax set-aside

Dated assumptions: draft content as checked 25 October 2026; tax and retirement figures are for tax year 2026 where stated. Verify current-year limits, rates, and deadlines before acting, as the IRS adjusts them annually.