Self-Employment Tax Calculator for 1099 Contractors
This follows Schedule SE line by line, including the part nearly every free calculator skips: if you also draw a paycheck, those wages use up the social security wage base before your business income touches it, and above the base your profit pays 2.9 percent instead of 15.3.
Worked example
These are the figures the calculator opens with and the answer it gives. Change anything above and every number below moves with it.
- Tax year2026, what you are paying estimates on now
- Net profit from the business62000 $
- W-2 wages from a job this year, 0 if none0 $
- Filing statusSingle, head of household or surviving spouse
Self-employment tax$8,760.32
This is self-employment tax and nothing else. Federal income tax, the qualified business income deduction and any state tax are on top of it, so do not set aside only this figure.
The $184,500.00 wage base for 2026 is from Publication 15 for 2026. The 2026 Schedule SE does not exist yet, because the IRS publishes a tax year's form after that year ends.
| Net profit | $62,000.00Schedule C line 31, which goes on Schedule SE line 2 |
|---|---|
| Net earnings | $57,257.00line 4a, profit times 92.35 percent, which takes out the employer half |
| Social security, 12.4% | $7,099.87line 10, charged on $57,257.00 of it |
| Medicare, 2.9% | $1,660.45line 11, charged on all of it, there is no cap |
| Self-employment tax | $8,760.32line 12, the two above added together |
| Wage base left for you | $184,500.00line 9, the $184,500.00 base for 2026 less the $0.00 of social security wages your job already used |
| Additional Medicare Tax | $0.00Form 8959, none due. It starts over $200,000.00 for single, head of household or qualifying surviving spouse, counting your wages first |
| Deduction on Schedule 1 | $4,380.16line 13, one half of the self-employment tax. It cuts the income you pay income tax on, it does not cut this bill |
| Share of your profit | 14.1%what these taxes take out of the profit before any income tax |
| Each quarter | $2,190.08if you pay estimates. This is the self-employment part only, income tax is on top of it |
What this calculator assumes
- Self-employment tax is social security and Medicare on money you earn for yourself: 12.4 percent for social security up to a yearly wage base, and 2.9 percent for Medicare with no cap at all. Schedule SE is the form that computes it and this page follows that form line by line.
- Line 4a multiplies your net profit by 92.35 percent before any tax is worked out. That is the form taking out the half an employer would have paid, so you are not taxed on the employer share of your own earnings.
- The social security wage base is the only figure here that changes from year to year. For 2026 it is $184,500, stated in Publication 15 for 2026. For 2025 it is $176,100, stated in the Schedule SE instructions. Both were read out of the IRS documents themselves and not out of anybody's summary.
- Wages from a job come first and this is the part most calculators get wrong. Schedule SE lines 7 to 9 take your W-2 social security wages off the wage base before your profit touches it, so a contractor with a day job pays the 12.4 percent on less of the profit, and above the base pays it on none.
- The Additional Medicare Tax is Form 8959: 0.9 percent on the amount over $200,000 single, $250,000 married filing jointly, $125,000 married filing separately. Your W-2 wages eat that threshold before any self-employment income touches it.
- One half of the self-employment tax is deductible on Schedule 1. It reduces the income you pay income tax on. It does not reduce this bill.
- If your net earnings come to less than $400 the form says stop, you do not owe self-employment tax.
- What is not here: federal income tax, the qualified business income deduction, state and local tax, the farm and nonfarm optional methods, church employee income, and the ministerial exemption. Each of those needs facts this page does not ask for, and a number that looks like a whole tax bill while silently leaving out income tax is worse than one that says exactly what it covers.
- If your W-2 wages come from two employers and together they pass the wage base, each employer caps social security separately and the excess comes back as a credit on your return. This page treats W-2 wages as one figure.
Where 15.3 percent comes from
Social security is 12.4 percent and Medicare is 2.9 percent. On a payroll job those are split down the middle: 7.65 percent comes out of the check and the employer pays a matching 7.65 percent that the employee never sees. Working for yourself you are both halves, which is the whole of the surprise.
Schedule SE softens it in one place. Line 4a multiplies your net profit by 92.35 percent before any tax is figured, which is the form taking out the employer share of your own earnings so you are not taxed on money you are being taxed on. That is why 15.3 percent of the profit is not the answer: 15.3 percent of 92.35 percent of it is, which works out at about 14.1 percent of the profit until the wage base bites.
It comes off the top, before any deduction on your 1040 and before the standard deduction. A contractor who owes no income tax at all can still owe this.
A paycheck changes the answer, and almost nothing on the web accounts for it
The 12.4 percent stops at a yearly wage base. Schedule SE lines 7 to 9 do the coordination: line 7 is the base, line 8 is the social security wages already reported in box 3 of your W-2, and line 9 is what is left. Only the smaller of your net earnings and that remainder pays the 12.4 percent.
So a contractor earning a wage somewhere and running a side business pays materially less than a calculator that ignores the day job will tell them, and one whose wages already pass the base pays no social security on the business at all, only the 2.9 percent Medicare part. Put the W-2 figure in and the page does the subtraction.
It works the same way in the other direction on Form 8959. The Additional Medicare Tax threshold is eaten by your wages first, so the 0.9 percent can start biting your self-employment income at a profit far lower than the threshold itself.
This year's wage base is not on this year's form
The wage base is the only figure in this calculation that moves from year to year, and it is the one most likely to be stale wherever you read it. The reason is mechanical: the IRS publishes a tax year's Schedule SE after that tax year has ended, so the newest Schedule SE on IRS.gov is always the one for last year.
Publication 15 runs the other way. Its edition is for the calendar year you are in, and it states the base you should be using for the estimates you are paying right now. This page carries both years and names the document each one came from, because a figure with no source behind it is the thing that quietly puts an estimate out by thousands.
It is not your whole tax bill
Self-employment tax is one line. Federal income tax is another, the qualified business income deduction can cut that one, and most states want something as well. A number that looks like a complete answer while silently leaving income tax out is worse than one that says exactly what it covers, so this page says it.
One half of the self-employment tax is deductible on Schedule 1. Read that carefully: it reduces the income your income tax is figured on. It does not reduce this bill by a cent.
If you want a figure to actually set aside, take the quarterly number here and add something for income tax on top. Contractors who put money aside per invoice rather than per quarter are the ones who are not scrambling in April.
Questions people ask
How much is self-employment tax?
15.3 percent, which is 12.4 percent for social security plus 2.9 percent for Medicare. It is charged on 92.35 percent of your net profit, so the effective rate on the profit itself is about 14.1 percent until your earnings pass the social security wage base.
Why is my profit multiplied by 92.35 percent?
Because an employer would have paid half of these taxes for you and that half would not have been your income. Schedule SE line 4a takes it out first so you are not taxed on the employer share of your own earnings.
I have a job and a side business. Do I pay social security twice?
No. Schedule SE lines 7 to 9 take the social security wages from your W-2 off the wage base before your business income is charged. If your wages already fill the base, your profit pays the 2.9 percent Medicare part only.
Do I owe self-employment tax on a small side income?
Not if your net earnings come to less than $400. Line 4c says to stop there. The income still goes on your return and income tax can still apply to it.
Is this the same as income tax?
No, and they are separate lines on your return. This is social security and Medicare on self-employment earnings. Federal income tax, the qualified business income deduction and state tax are all on top of it and are not calculated here.
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