Self-Employment Tax Calculator
It works out the Social Security and Medicare tax owed on self-employment profit — the 15.3% that an employer would otherwise have split with you.
Self-employment tax
$14,129.55
Net earnings (92.35%)
$92,350
Social Security 12.4%
$11,451.40
Medicare 2.9%
$2,678.15
Additional Medicare
$0.00
Deductible half
$7,064.78
Wage base
$184,500
Estimate only, and not tax advice. Federal income tax is charged on this same profit separately — confirm your position with a tax professional.
What it calculates
It works out the Social Security and Medicare tax owed on self-employment profit — the 15.3% that an employer would otherwise have split with you.
Why it matters
It is the tax that surprises new freelancers. Employees see 7.65% withheld and never think about it; the self-employed owe both halves and must set the money aside themselves.
Who it's for
Freelancers, contractors, gig workers, single-member LLC owners and anyone with a side business filing Schedule C.
Formula
- NP
- Net profit — business income less expenses
- NE
- Net earnings, which is 92.35% of net profit
- SS
- Social Security at 12.4%, capped at the wage base
- MC
- Medicare at 2.9%, with no cap
Worked example
$100,000 of net profit, no W-2 job
- 1Net earnings = 100,000 × 0.9235 = $92,350
- 2Social Security = 92,350 × 12.4% = $11,451.40
- 3Medicare = 92,350 × 2.9% = $2,678.15
- 4Half of the total is deductible against income tax
$14,129.55 of self-employment tax, or $3,532.39 a quarter
How the self-employment tax calculator works
Only 92.35% of net profit is subject to the tax. That factor is (1 − 7.65%), and it exists so you are not taxed on the employer-equivalent half that an employee would never have received as wages. Social Security takes 12.4% of net earnings up to the annual wage base; Medicare takes 2.9% of everything with no ceiling. Above $200,000 ($250,000 married), an extra 0.9% Additional Medicare applies. If you also have a salaried job, those W-2 wages fill the Social Security cap first, so a high salary can leave little or none of the cap for your business income.
Only 92.35% of net profit is taxed. That factor is (1 − 7.65%), and it exists so you are not charged on the employer-equivalent half an employee would never have received.
Social Security stops at the annual wage base. Medicare never does, which is why a very profitable year keeps adding tax long after the Social Security portion has flattened.
Common mistakes
- Applying 15.3% to gross revenue instead of to net profit after expenses.
- Forgetting that a W-2 salary already used up part of the Social Security wage base.
- Overlooking the deductible half, which lowers the income tax bill on the same profit.
- Treating this as your whole tax bill — federal income tax is charged on the same profit as well.
Tips and best practice
- Move roughly 30% of every payment into a separate account the day it lands.
- Track deductible expenses obsessively: every dollar of expense saves both income and self-employment tax.
- Pay quarterly estimates on time; the underpayment penalty is charged even if you settle up in April.
Frequently asked questions
How much is self-employment tax?
It is 15.3% of net earnings — 12.4% for Social Security up to the annual wage base, plus 2.9% for Medicare with no cap. Net earnings are 92.35% of your net profit.
Do I pay self-employment tax on gross income?
No. It applies to net profit after business expenses, and then only to 92.35% of that figure. Deducting legitimate expenses lowers this tax directly.
Can I deduct self-employment tax?
Half of it is an above-the-line deduction against income tax. It does not reduce the self-employment tax itself, only the income tax charged on the same profit.
What if I have a job as well as a business?
Your W-2 wages fill the Social Security wage base first. If your salary already exceeds the cap, your business profit owes Medicare tax but no further Social Security.
When do I have to pay it?
In quarterly estimated payments, generally due in April, June, September and January. The calculator divides your annual figure by four as a starting point.
Related calculators
Methodology & trust
- Formula source
- IRS Schedule SE and SSA wage base announcements for 2026
- Last updated
- 2026-07-28
- Privacy
- Every calculation runs in your browser. No inputs are sent to a server or stored.