Self-Employment Tax Calculator
Compute the 15.3% Schedule SE tax owed by sole proprietors, single-member LLC owners, partners, freelancers, and gig workers. Includes the Social Security wage cap, uncapped Medicare portion, the 0.9% Additional Medicare surtax for high earners, and the half-deductible above-the-line. 2026 constants per IRS Schedule SE and IRC §1401.
Schedule C profit × 92.35%
Above-the-line, Schedule 1 line 15
- Social Security portion (12.4%)$9,161
- Medicare portion (2.9%)$2,143
- Additional Medicare (0.9%)$0
SS wage base used: $176,100 · Single
View the TypeScript implementation on GitHub: packages/calc/src/self-employment-tax.ts · view tests
Self-employment tax at a glance
Key facts
- The rate
- Self-employment tax is 15.3% — 12.4% Social Security plus 2.9% Medicare — on net self-employment earnings. W-2 employees split these taxes 50/50 with their employer; the self-employed pay both halves (IRC §1401).
- The $400 floor
- SE tax applies to anyone who nets $400 or more from self-employment in a year (IRC §1402(b)(2)) — sole proprietors, single-member LLC owners, general partners, and 1099 contractors. Below $400, no SE tax is owed.
- The 92.35% multiplier
- Net SE earnings = Schedule C profit × 92.35% before the 15.3% rate applies (IRC §1402(a)(12)). The 7.65% reduction mirrors the employer-side FICA a W-2 employee never sees — without it, the self-employed would pay tax on tax.
- The half-deduction
- Half of the regular SE tax is deductible above the line (IRC §164(f)), reducing AGI. The deduction covers only the 12.4% + 2.9% portions — the 0.9% Additional Medicare surtax is not deductible.
- The 0.9% surtax
- An Additional Medicare Tax of 0.9% (IRC §1401(b)(2)) applies to combined wages + SE earnings above $200,000 single / $250,000 MFJ / $125,000 MFS — thresholds that are not indexed for inflation, so they catch more taxpayers each year.
- The wage-base cap
- The 12.4% Social Security portion stops at the wage base — $176,100 for 2026 per the SSA Contribution and Benefit Base — and the base is shared with any W-2 wages earned the same year. The 2.9% Medicare portion is uncapped.
Rules per IRS Schedule SE (Form 1040) and 26 U.S.C. §1401; wage base per the SSA Contribution & Benefit Base. Updated May 2026.
What this means
SE tax is the 15.3% combined Social Security + Medicare hit that every sole proprietor, single-member LLC owner, partner, and 1099 contractor pays on their net business profit. W-2 employees split these taxes 50/50 with their employer; you pay both halves. The 92.35% multiplier on the front end reflects what the employer-side FICA would have been; the half-deduction on the back end gives you an above-the-line write-off for the "employer half" of what you paid. Net of those two adjustments, the effective burden on a "reasonable" mix of SE income lands closer to 13–14% than the headline 15.3%.
Two interactions trip up new filers. First, the SS wage base ($176,100 for 2026 per SSA Contribution & Benefit Base) is shared with any W-2 wages you earned the same year, so a side-hustler with $150K of W-2 income and $50K of SE income only pays the 12.4% SS rate on the first $26,100 of their SE earnings. Second, the 0.9% Additional Medicare surtax kicks in above $200K (single) / $250K (MFJ) of combined wages + SE earnings, is reported on Form 8959, and — unlike the regular 15.3% — is not deductible.
Worked example
Solo freelance consultant, $80,000 of net Schedule C profit, no W-2 income, single filer. Step 1: net earnings from SE = $80,000 × 0.9235 = $73,880. Step 2: above the $400 floor, so SE tax applies. Step 3: SS portion = $73,880 × 0.124 = $9,161.12 (under the $176,100 cap, so not capped). Step 4: Medicare portion = $73,880 × 0.029 = $2,142.52. Step 5: combined Medicare-eligible income = $73,880, well under the $200K single threshold, so no additional Medicare surtax. Step 6: total SE tax = $11,303.64; above-the-line deduction = $11,303.64 / 2 = $5,651.82. The "15.3%" rule of thumb applies to net earnings AFTER the 92.35% multiplier — the effective rate against the original $80,000 profit is about 14.13%.
Frequently asked questions
The information and tools on this website are for general educational purposes only and do not constitute financial, investment, legal, or tax advice. Consult a licensed professional for decisions specific to your situation.