Is this tax in addition to income tax?

Yes — self-employment tax funds Social Security and Medicare specifically, separate from federal (and possibly state) income tax owed on the same net profit. Budget for both.

What's the Social Security wage base for?

The 12.4% Social Security portion only applies up to a capped amount of earnings each year ($184,500 for 2026) — earnings above that cap owe no additional Social Security tax, though the 2.9% Medicare portion has no cap at all.

Can I deduct the full self-employment tax?

No — only half of the 'regular' 15.3% (Social Security + Medicare) portion is deductible as an adjustment to income on your Form 1040. The 0.9% Additional Medicare Tax, when it applies, is never deductible.

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Self-Employment Tax Calculator

Social Security and Medicare tax owed on freelance or business income.

🔒 Runs entirely in your browser — nothing here is ever uploaded

Last reviewed 2026-08-25

About the Self-Employment Tax Calculator

Estimates the Social Security and Medicare tax owed on self-employment income — the equivalent of the FICA tax an employer would otherwise split with you — plus the above-the-line deduction you get for half of it.

How to use it

Enter your Net self-employment profit (Schedule C net profit, or net business income).
Read your total self-employment tax, its Social Security and Medicare components, and the deductible half in the result panel.

Formula

Taxable earnings = net profit × 92.35%
Social Security portion = min(taxable earnings, $184,500) × 12.4%
Medicare portion = taxable earnings × 2.9%
Additional Medicare Tax = max(0, taxable earnings − $200,000) × 0.9% (single filer)

The 92.35% factor and the split rates come directly from IRS Schedule SE — it exists because a traditional employee's employer pays half of FICA tax on their behalf (7.65%), income a self-employed person never has withheld in the first place, so the 15.3% combined rate applies to a slightly reduced base instead.

Worked example

$80,000 in net self-employment profit produces $73,880 in taxable earnings (92.35%), all under the $184,500 Social Security wage base — for $9,161 in Social Security tax plus $2,143 in Medicare tax, an $11,304 total self-employment tax, with $5,652 deductible as an adjustment to income.

Interpreting your result

Only federal self-employment tax is estimated here — this is in addition to, not instead of, federal and state income tax on the same profit. Only the 'regular' 15.3% (Social Security + Medicare) portion gets the above-the-line half-deduction; the 0.9% Additional Medicare Tax is never deductible.

Recommendations

• The deductible half reduces your income tax, not your self-employment tax itself — you still owe the full self-employment tax amount; the deduction just lowers what you're taxed on separately for income tax purposes.
• Quarterly estimated tax payments are usually required once you owe more than $1,000 in combined income and self-employment tax for the year — check the IRS's estimated tax rules to avoid an underpayment penalty.
• If you also have W-2 wage income the same year, your combined wages and self-employment earnings share the same Social Security wage base — this calculator doesn't account for W-2 income, so treat the estimate as your self-employment income considered in isolation.

Frequently asked questions

It approximates the employer-equivalent share of FICA tax a traditional employee's wages never have withheld in the first place — a self-employed person is effectively both employer and employee, and Schedule SE builds this adjustment in before applying the 15.3% rate.