Work out US self-employment tax (Schedule SE) for tax year 2025 from your net self-employment earnings: the 92.35% taxable amount, 12.4% Social Security up to the 2025 wage base, 2.9% Medicare on everything, the 0.9% Additional Medicare Tax at higher incomes — and the half of the tax you can deduct. Everything updates live in your browser — nothing is uploaded. Rates checked 29 October 2026 — US tax year 2025.
Rates checked 29 October 2026 — US tax year 2025. SE rates and the 92.35% factor: IRS Topic No. 554 (self-employment tax) — 12.4% Social Security + 2.9% Medicare on 92.35% of net earnings, and you may deduct one-half of the SE tax. Social Security wage base for 2025: $176,100 (Social Security Administration, Contribution and Benefit Base / 2025 COLA fact sheet). Additional Medicare thresholds: $200,000 single and head of household, $250,000 married filing jointly (IRS Topic No. 554 and the IRS Additional Medicare Tax Q&A). This calculator covers SE tax only — your federal income tax on the profit is separate.
The deductible half is 50% of the Social Security + Medicare parts of the SE tax. Rule used here: the 0.9% Additional Medicare Tax is not part of the deductible half — it is figured on Form 8959, not on Schedule SE, and the Schedule SE deduction is one-half of the Schedule SE tax (IRS Topic No. 554). The deduction lowers your income tax; it does not reduce the SE tax itself.
The same steps Schedule SE takes, in order. Social Security is the only capped part; Medicare runs on the full taxable amount.
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Work out US self-employment tax for tax year 2025 — the 92.35% taxable amount, 12.4% Social Security up to the $176,100 wage base, 2.9% Medicare, 0.9% Additional Medicare and the deductible half.
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Work out US self-employment tax for tax year 2025 (rates checked 29 October 2026) from your net self-employment earnings: the 92.35% taxable amount, 12.4% Social Security up to the $176,100 wage base (reduced by any W-2 wages), 2.9% Medicare on the full amount, the 0.9% Additional Medicare Tax past your filing-status threshold, the total SE tax, a suggested quarterly estimated payment, and the half of the tax you can deduct.
Net self-employment earnings of $100,000, no W-2 wages, single filer, tax year 2025. Taxable SE amount = $100,000 × 92.35% = $92,350 (IRS Topic No. 554). Social Security = $92,350 × 12.4% = $11,451.40 — the full amount fits under the 2025 wage base of $176,100 (Social Security Administration). Medicare = $92,350 × 2.9% = $2,678.15. Combined income is under the $200,000 Additional Medicare threshold, so that part is $0. Total SE tax = $11,451.40 + $2,678.15 = $14,129.55, an effective rate of 14.13% on net earnings, and the deductible half is $14,129.55 ÷ 2 = $7,064.78. Rates checked 29 October 2026 — US tax year 2025.
SE tax is figured on 92.35% of net earnings — the adjustment that stands in for the employer share an employee never sees (IRS Topic No. 554). Social Security is 12.4% of the taxable amount, capped so that W-2 wages plus the SE amount taxed at 12.4% cannot exceed the wage base — $176,100 for 2025 (SSA Contribution and Benefit Base); W-2 wages consume the base first. Medicare is 2.9% of the full taxable amount with no cap. The Additional Medicare Tax is 0.9%: as a documented simplification, the excess is measured on W-2 wages plus the taxable SE amount combined, and the 0.9% applies only to the SE share of that excess. Total SE tax is the sum of the three parts. The deductible half is 50% of the Social Security + Medicare parts only — the rule used here is that the 0.9% Additional Medicare Tax, figured on Form 8959 rather than Schedule SE, is not part of the deductible half.
Employees are never taxed on the employer’s half of payroll tax, so the tax code gives the self-employed the equivalent break: only 92.35% of net earnings (100% minus the 7.65% employer-equivalent share) is subject to SE tax (IRS Topic No. 554). On $100,000 of net earnings the taxable amount is $92,350.
It is the maximum earnings the 12.4% Social Security part applies to — $176,100 for 2025 (Social Security Administration). Medicare’s 2.9% has no cap. At net earnings of $250,000 the taxable amount is $230,875, but Social Security is charged only on $176,100 of it: $21,836.40, not $28,628.50.
Wages from a job are taxed for Social Security first, so they consume wage-base room: with $100,000 of W-2 wages only $176,100 − $100,000 = $76,100 of room is left, and the 12.4% part applies to at most that much of your SE amount. Your wages also count toward the Additional Medicare threshold.
You may deduct one-half of your SE tax when figuring adjusted gross income (IRS Topic No. 554). The rule used here: the deductible half is 50% of the Social Security + Medicare parts from Schedule SE — the 0.9% Additional Medicare Tax is figured on Form 8959 and is not part of that half. The deduction reduces your income tax; it does not reduce the SE tax itself.
When wages plus self-employment income pass $200,000 for single and head-of-household filers or $250,000 for married filing jointly (IRS Topic No. 554). In this calculator the 0.9% applies to the SE share of the excess over that threshold, combining any W-2 wages you entered.
No. SE tax is Social Security and Medicare only. The same profit is also subject to federal income tax (and usually state tax), calculated separately — SE tax is the part new sole proprietors most often forget when they set money aside.
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