Self-Employment Tax Calculator
Exact Schedule SE math — including the 92.35% multiplier and the half-SE deduction most filers forget — so you see your true rate, not the headline 15.3%.
Written by Dorothy Ibrahim, 10+ years in banking & finance
Reviewed by Benton Jona, EA (Enrolled Agent) — 2026-07-13
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How we calculate this
This calculator runs the exact Schedule SE math on your net self-employment income, including the two breaks filers most often miss: the 92.35% net-earnings multiplier and the half-SE deduction. Together they mean your true SE rate on gross income is meaningfully below the headline 15.3%. It also accounts for W-2 wages from a day job, which use up Social Security wage-base room first and can shrink the SE tax you owe on side income.
The formulas
- Net earnings from self-employment
- net self-employment income × 0.9235If net earnings are under $400, no SE tax is due at all (IRS filing minimum).
- Social Security portion
- 12.4% × min(net earnings, Social Security wage base − W-2 wages already earned)The wage base is $184,500 for 2026 ($176,100 for 2025); W-2 wages consume it first.
- Medicare portion
- 2.9% × net earnings (no cap)
- Additional Medicare tax
- 0.9% × max(0, net earnings + W-2 wages − threshold)Thresholds: $200,000 single/HOH, $250,000 MFJ, $125,000 MFS.
- Half-SE deduction (above the line)
- 0.5 × (Social Security portion + Medicare portion)Reduces income tax even if you take the standard deduction.
Worked example
- Take the defaults: $85,000 of net self-employment income, no W-2 wages, single filer, tax year 2026.
- Net earnings = $85,000 × 0.9235 = $78,497.50.
- Social Security = 12.4% × $78,497.50 = $9,733.69 (well under the $184,500 wage base); Medicare = 2.9% × $78,497.50 = $2,276.43.
- SE tax = $9,733.69 + $2,276.43 = $12,010.12 — an effective 14.13% of gross, not 15.3%, thanks to the 92.35% multiplier.
- The half-SE deduction is $6,005.06, which at the 22% bracket saves about another $1,321.11 of income tax.
Rates, benchmarks & sources
- SE tax rates (12.4% + 2.9%), the $184,500 Social Security wage base for 2026 ($176,100 for 2025), the 92.35% multiplier, the $400 filing minimum, and the 0.9% additional Medicare thresholds — SSA (2025-10-24); IRS; PayrollOrg (2026)
- The calculation structure: net-earnings multiplier, half-SE deduction, and the additional Medicare tax computation — IRS Schedule SE (Form 1040) / Form 8959
- 2026 income-tax brackets used to value the half-SE deduction at your marginal rate — IRS Rev. Proc. 2025-32
Figures current as of 2026-07-02. See our methodology & editorial standards for how constants are versioned and verified.
What this tool doesn’t model
- Federal only — SE tax is federal; state income tax on the same income is not modeled, and this estimate is not filing advice.
- It computes SE tax in isolation: federal income tax on the same income is a separate (larger) number — the Business Income Tax estimator combines the two.
- "Net self-employment income" means profit after business expenses; the tool does not audit whether your expense number is complete or deductible.
- Church employee income, farm optional methods, and statutory-employee edge cases on Schedule SE are not modeled.
- The W-2 interaction assumes your listed wages were all Social Security-taxable wages; certain pretax benefits can make the true SS wage figure differ from gross salary.
Frequently asked questions
Why is my rate not the 15.3% everyone quotes?
Two built-in breaks lower it. First, SE tax applies to only 92.35% of your net profit — that multiplier stands in for the employer-half deduction W-2 workers effectively get. Second, half of the SE tax itself is deductible against income tax. In the default $85,000 example, tax is $12,010.12 — 14.13% of gross — and the $6,005.06 half-SE deduction saves roughly another $1,321 of income tax at the 22% bracket.
I have a day job and freelance on the side — do I pay SE tax twice?
You never pay Social Security tax on more than the wage base ($184,500 for 2026) across all earnings combined. Your W-2 wages fill the base first, so only the room left over is subject to the 12.4% SE Social Security portion. Medicare has no cap, so the 2.9% applies to all net earnings, and the 0.9% additional Medicare tax kicks in once combined earnings pass your filing-status threshold.
What counts as net self-employment income?
Your gross receipts minus ordinary and necessary business expenses — the bottom line of Schedule C for a sole proprietor, or your share of partnership self-employment earnings. It is not your revenue. Deductions like home office, mileage, and equipment reduce this number and therefore reduce SE tax too, which is why expense tracking matters twice: once for income tax and again here.
Is there a minimum income before SE tax applies?
Yes — if your net earnings (income × 0.9235) come to less than $400 for the year, no self-employment tax is due and Schedule SE is not required for that income. Cross $400 and the tax applies to the whole amount, not just the excess. Note this is the SE-tax threshold specifically; the income can still be subject to income tax and still must be reported.
Does this include federal and state income tax?
No — SE tax is only the Social Security and Medicare piece. Federal income tax on the same profit is separate and usually larger; state income tax is separate again and not modeled anywhere in this tool. For the combined federal picture use the Business Income Tax estimator, and treat all of it as a planning estimate rather than filing advice.
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Federal figures only unless noted. State taxes vary.