Quick answer
On $100,000 of net self-employment earnings in 2026, self-employment tax is $14,129.55: $11,451.40 of Social Security tax and $2,678.15 of Medicare tax, an effective rate of 14.13%. Half of that tax — $7,064.78 — is deductible from your income tax, saving about $1,554 at a 22% marginal rate.
How the Self-Employment Tax Calculator works, step by step
Enter your net earnings from self-employment — your Schedule C net profit, revenue minus deductible business expenses — and your filing status. The calculator follows Schedule SE: it first reduces net earnings by any home-office deduction you enter, then multiplies by 92.35% to find the SE-tax base. That 92.35% step exists because employees never pay payroll tax on the employer's share; the self-employed get the same treatment through the multiplier.
Social Security tax is 12.4% of the base, but only up to the 2026 wage base of $184,500. On the $100,000 example the base is $92,350, so the full base is taxed and Social Security takes $11,451.40. The cap starts to matter once net earnings pass about $199,800 — above that, the Social Security line stops growing while Medicare keeps rising.
Medicare tax is 2.9% of the full base with no cap — $2,678.15 on the example. High earners pay an additional 0.9% Medicare tax on the base above $200,000 for single filers or $250,000 for married couples filing jointly. The threshold is set by your filing status, which is why the calculator asks for it.
The home-office deduction is an optional input that reduces net earnings before the calculation starts. A $2,760 deduction on the example cuts the base to $89,801 and the total tax to $13,740, saving about $390 of SE tax. Enter whatever home-office deduction you claim — the simplified $5-per-square-foot method or actual expenses — or leave it at zero.
The deduction for one-half of SE tax softens the bill on the income-tax side. You deduct half the SE tax — $7,064.78 on the example — from your income when figuring federal income tax, which at a 22% marginal rate saves about $1,554. It does not reduce the SE tax itself, and it is not the same as the 20% QBI deduction, which lowers income tax further. The calculator shows the effective rate too: 14.13% on the example, because the 92.35% step means the 15.3% rate applies to less than your full earnings.
The formula
SE-tax base = (net earnings − home-office deduction) × 92.35%. Social Security tax = 12.4% of the base up to $184,500. Medicare tax = 2.9% of the base, plus 0.9% above $200,000 single or $250,000 joint. Total SE tax = Social Security + Medicare. One-half of SE tax is deductible for income tax.
Worked example — try it on the calculator above
Worked example: $100,000 net earnings, single filer, 2026
Net earnings are $100,000 with no home-office deduction. The SE-tax base is $100,000 × 92.35% = $92,350. Social Security tax is 12.4% of the base, $11,451.40, and Medicare tax is 2.9%, $2,678.15. Total SE tax is $14,129.55, an effective rate of 14.13% on net earnings, leaving $85,870.45 after SE tax. The one-half deduction is $7,064.78, worth about $1,554 of income-tax saving at a 22% marginal rate. The base is well below the $200,000 additional-Medicare threshold, so no 0.9% tax applies. Claiming a $2,760 home-office deduction would cut the base to $89,801 and the tax to $13,740.
Frequently Asked Questions
What is the self-employment tax rate?
15.3% on 92.35% of net earnings: 12.4% for Social Security up to the $184,500 wage base for 2026, plus 2.9% for Medicare on all earnings. Because the 92.35% step shrinks the base first, the effective rate on net earnings is 14.13% below the wage base. Above $200,000 of earnings ($250,000 married filing jointly), an additional 0.9% Medicare tax applies.
Why is the SE-tax base 92.35% of net earnings?
Employees pay payroll tax only on their wages, never on the employer's matching share. The self-employed are both employer and employee, so Schedule SE multiplies net earnings by 92.35% — roughly 100% minus the 7.65% employer share — before applying the 15.3% rate. It is the same treatment, applied through the multiplier instead of a separate employer payment.
What is the deduction for one-half of SE tax?
You may deduct half of your self-employment tax from your income when figuring federal income tax. On $100,000 of net earnings the deduction is $7,064.78, worth about $1,554 at a 22% marginal rate. It lowers income tax only — it does not reduce the SE tax itself — and it is separate from the 20% QBI deduction.
Does a home-office deduction lower self-employment tax?
Yes. A home-office deduction claimed on Schedule C reduces your net earnings before the SE-tax calculation, so it lowers both income tax and SE tax. A $2,760 deduction on $100,000 of net earnings cuts SE tax by about $390. Enter your deduction in the calculator, or leave it at zero if you do not claim one.
Estimates, not advice. This calculator provides educational estimates based on the inputs you enter and the assumptions shown on this page. It is not financial, tax or investment advice, and it cannot see your full situation. Verify important figures against official sources, and consider a qualified professional for decisions about your own money. See our Disclaimer and Methodology.