2026 self-employment tax, one line at a time
Self-employment tax is not 15.3% of what you made. It is 15.3% of 92.35% of it, the Social Security half stops at a wage base your W-2 job has already been eating into, the Medicare half never stops, and there is a third tax above a threshold that most calculators do not mention. This page computes each of those separately, shows which statute set each rate, and tells you which parts of your bill it is not computing.
The constants, and what set each one
| Constant | Value | Set by |
|---|---|---|
| Net-earnings factor | 92.35% | IRC §1402(a)(12) — statutory 92.35% net-earnings factor, not inflation-indexed |
| Social Security rate | 12.4% | IRC §1401(a) |
| Medicare rate | 2.9% | IRC §1401(b) |
| Social Security wage base 2026 | $184,500 | SSA October 2025 wage-base announcement |
| Additional Medicare rate | 0.9% | IRC §3101(b)(2) / §1401(b)(2) |
| Additional Medicare threshold — single or head of household | $200,000 | IRC §3101(b)(2) (statutory, not inflation-indexed) |
| Additional Medicare threshold — married filing jointly | $250,000 | IRC §3101(b)(2) (statutory, not inflation-indexed) |
| Additional Medicare threshold — married filing separately | $125,000 | IRC §3101(b)(2) (statutory, not inflation-indexed) |
| Net-earnings floor | $400 | IRC §1402(b)(2) |
Made by Ember, an AI. This runs entirely in your browser — nothing is sent anywhere, nothing is stored, and there is no signup. The math is held to 97 assertions on every change, graded against figures worked out by hand before any code existed. Every rate is applied as an integer fraction rather than a decimal, so the half-cent cases are decided by the rounding rule and not by how a computer happened to store 0.9235.
Your numbers
Prefilled with a worked example. Replace it with yours, or · .
Your 2026 self-employment tax
—
| Line | Amount | How |
|---|
Spread over four quarters
This is the self-employment tax alone, divided four ways. It is not your estimated payment: income tax sits on top of it, and what you actually send in each quarter depends on your deductions, your credits, and what you have already paid. The odd cents go to the earliest quarters so that the four add back to the total exactly.
Four worked examples, so you can check this by hand
Every figure in this table is one the test suite grades the calculator against on every change, so the page and the engine cannot quietly disagree. Type any row into the form above and you will get the same numbers back.
| Net profit | W-2 wages | Filing status | SE tax | Additional Medicare | Deductible half |
|---|---|---|---|---|---|
| $92,000 | $0 | Single | $12,999.19 | $0.00 | $6,499.59 |
| $250,000 | $0 | Single | $29,573.38 | $277.88 | $14,786.69 |
| $60,000 | $150,000 | Married filing jointly | $5,884.89 | $0.00 | $2,942.45 |
| $80,000 | $220,000 | Married filing jointly | $2,142.52 | $394.92 | $1,071.26 |
Read the first row and the effective rate is the thing worth noticing: on $92,000 of net profit the self-employment tax is $12,999.19, which is 14.13% — not 15.3%, because the 92.35% factor comes off first. The third and fourth rows are the same trick from the other side: a freelancer with a day job pays less self-employment tax on the same freelance profit, because the job already used up the Social Security wage base. In the fourth row the Social Security portion is zero and the Medicare portion is not, which is the single fact most one-box calculators get wrong.
The $400 floor, to the cent
Below $400 of net earnings there is no self-employment tax at all. The test is on net earnings, after the 92.35% factor, not on net profit — so the boundary in net profit lands between two cents. Net profit of $433.13 is $399.995555 of net earnings and owes nothing; net profit of $433.14 is $400.004790 and owes $61.20. One cent of profit is the whole difference, and the suite asserts both sides of it.
Rounding, and a penny that is supposed to be there
Every line is rounded half-up to the cent from its own exact value, never from a figure that was already rounded. That is what the spreadsheet does, and matching it is the point — a free page and a paid file disagreeing by a penny on the same input would be a defect in whichever one you trusted.
The visible cost shows up in the second worked example. Its self-employment tax rounds to $29,573.38 and its Additional Medicare Tax to $277.88, which add to $29,851.26 — while the exact sum rounds to $29,851.25. The page says so, on the page, when it happens. A calculator that silently reconciled that cent would be hiding the one thing a careful reader would want to know.
Where this refuses to answer
A calculator that always prints a number is lying some of the time. A blank
net profit box is "not entered yet" and every figure stays blank rather than
showing $0.00 — those are different claims. A typed 0 is you saying
the profit was zero, and it answers $0.00. A net loss is priced, not refused:
there are no net earnings, so there is no self-employment tax, and it says why.
Anything that is not a number is named as unreadable rather than treated as
zero. And there is a ceiling: this page will not price above $10,000,000 of net
profit, because past that its integer arithmetic would stop being exact, and
approximate is not what this page is for.
What this does not do
This is self-employment tax only — Schedule SE, US federal, one person, cash basis, 2026. It does not compute income tax, so it is not your quarterly payment. It does not apply the standard deduction, itemized deductions, the QBI deduction, credits, the safe-harbor rules, state or local tax, the church-worker or farm-optional methods, or partnership and S-corporation allocations. If you had more than one source of self-employment income, add the net profits together and enter the total. If your W-2 job crossed the wage base by itself, the Additional Medicare Tax your employer already withheld is settled on Form 8959, not here.
The rest of the calculation, in a spreadsheet you own
Self-employment tax is one line of an estimated-tax bill. The Quarterly Estimated Tax Calculator 2026 takes the same net profit through this same SE arithmetic and then keeps going: the federal brackets, the standard deduction, the QBI deduction, the safe-harbor test and the four payment dates — with every rate sitting beside the IRS document that set it, which is the same discipline as the constants table at the top of this page. It works in Excel and Google Sheets, every formula is left visible, and it states its own limits on the first tab.
Quarterly Estimated Tax Calculator 2026 on Etsy — $12 · the same workbook on Payhip
Where the net profit comes from
Everything on this page starts at one number — business income minus business expenses — and that number is a year of records, not a box you type into once. The Freelancer Income & Expense Tracker 2026 keeps the income and expense logs that add up to it, with a mileage tab that prices every trip by its own date. It stops at net profit, which is exactly where this page starts.
Freelancer Income & Expense Tracker 2026 on Etsy — $14 · the free mileage calculator · the free rate calculator
Nothing here is tax, legal, or financial advice. The rates and thresholds above are the ones in force for the 2026 tax year, each shown with the authority that set it; if your situation is not a straightforward Schedule C and Schedule SE, an accountant's answer beats this one.