How this self-employment tax calculator 2026 works
Subject earnings = 0.9235 × net profit; 12.4% up to the $184,500 wage base plus 2.9% on everything (plus 0.9% additional Medicare above $200k/$250k MAGI). You may deduct the employer-equivalent portion (the half shown above) on Schedule 1 — this calculator nets it out separately. Loss years: SE tax is zero on a net loss, but you can't deduct a negative either. Not modeled: the QBI 20% income-tax deduction, which lives on top of these numbers for most solo businesses.
Frequently asked questions
Why is self-employment tax 15.3% instead of 7.65%?
You ARE the employer: SECA combines both FICA halves — 12.4% Social Security + 2.9% Medicare. The employer-equivalent half is deductible from your income tax, which this tool quantifies, softening it to roughly 14% of net profit in cash terms.
What's the 92.35% rule?
The IRS simulates the employer's deduction: you pay SE tax on 92.35% of net earnings, not 100%. That's why the effective rate shown is slightly under 15.3%. Wages from a day job count against the $184,500 SS base FIRST, which can shrink your SS portion — enter payroll wages as negative offset on Sch SE if that applies.
When are quarterly payments due?
Form 1040-ES vouchers: Apr 15, Jun 16, Sep 15, Jan 15 for 2026–2027. Underpay less than 90% of this year's (or 100% of last year's) liability and the IRS adds an underpayment penalty — the quarterly column gives you the even split.