Estimator only, built from IRC §§1401–1402, Schedule SE, and the SSA sources cited below. Not tax advice. Runs entirely in your browser.
How this is calculated
| Step | Rule |
|---|---|
| 1. Net earnings | Net profit × 92.35% — the law's way of treating you like an employee whose wages exclude the employer's share (IRC §1402(a)(12)) |
| 2. Social Security | 12.4% of net earnings, only up to the wage base — and your W-2 wages consume the base first |
| 3. Medicare | 2.9% of all net earnings, no cap |
| 4. Additional Medicare | 0.9% on earnings above $200,000 ($250,000 joint / $125,000 separate), figured on Form 8959 — shown separately because it is not part of Schedule SE tax |
| 5. Deductible half | Half of the Schedule SE tax (steps 2 + 3) is an above-the-line deduction on Schedule 1 — it lowers income tax, never the SE tax itself |
The “effective” view: the half-deduction is worth your marginal income-tax rate times half the SE tax. The result panel estimates that using the federal brackets for a return whose only income is this profit (after the half-deduction and the standard deduction) — a simplification, labeled as such. If you have other income, your real marginal rate is the better guide.
Worked example (check it by hand)
Net profit $80,000, no W-2 wages, 2026. Net earnings: $80,000 × 92.35% = $73,880. Social Security: $73,880 × 12.4% = $9,161.12. Medicare: $73,880 × 2.9% = $2,142.52. Total SE tax $11,303.64, deductible half $5,651.82. Split evenly, that's $2,825.91 per quarterly estimated payment for the SE-tax portion. The calculator's default inputs reproduce this example.
Also drawing a paycheck from a job? See what a salary actually nets after federal withholding and FICA: paycheck calculator →
Frequently asked questions
Why 92.35%?
Employees never pay FICA on their employer's 7.65% share. Multiplying by 92.35% (100% − 7.65%) puts the self-employed on the same footing, per §1402(a)(12).
Do I owe SE tax on a tiny side gig?
Schedule SE tax applies once net earnings reach $400. Below that, no SE tax (income tax rules are separate).
Is the estimated schedule my whole quarterly payment?
No — the schedule below splits the SE-tax portion into four. Your actual Form 1040-ES payment also includes estimated income tax on the profit. Add the two before you pay.
What if my W-2 wages already exceed the wage base?
Then the Social Security part of SE tax is $0 and only Medicare (plus any Additional Medicare Tax) applies. Enter your wages in the optional field and the calculator handles it.
Sources
- Internal Revenue Code §1401 (rates: 12.4% + 2.9%) and §1402(a)(12) (the 92.35% factor); Schedule SE (Form 1040) and its instructions, including line 13 → Schedule 1, line 15 for the deductible half.
- Social Security Administration, 2026 COLA Fact Sheet — maximum taxable earnings $176,100 (2025) → $184,500 (2026); combined rates 7.65% employee / 15.30% self-employed; Additional Medicare Tax over $200,000 / $250,000: ssa.gov/news/en/cola/factsheets/2026.html.
- Form 8959 (Additional Medicare Tax) — the 0.9% is figured separately from Schedule SE and excluded from the deductible half.
- IRS Publication 505 / Form 1040-ES — quarterly estimated payment due dates shown in the results.
Last updated October 20, 2026. Estimator only — not tax advice. Church-employee, railroad, and optional-method (farm/nonfarm) cases follow different Schedule SE paths and are out of scope here.
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