Self-Employment Tax Calculator

What this self-employment tax calculator does

Calculates the self-employment tax you owe on your net self-employment earnings — the Social Security and Medicare contributions the IRS collects through Schedule SE instead of payroll withholding, since there's no employer to withhold it for you. Enter your net earnings (business income after expenses, not gross revenue) and your filing status, and it breaks down the Social Security portion, the Medicare portion, any Additional Medicare Tax, and the deductible half.

How the tax is calculated

That base is taxed in two parts: 12.4% for Social Security, capped once your Social Security-taxable earnings for the year — self-employment and any W-2 wages combined — reach the annual wage base, and 2.9% for Medicare, which never caps. Above a filing-status-specific threshold, an extra 0.9% Additional Medicare Tax applies on top of the 2.9%, also uncapped. Add all three together for your total self-employment tax; half of the Social Security and Medicare portions (not the Additional Medicare Tax) is deductible from your income for federal income tax purposes.

A worked example

Say you're a single filer with $60,000 in net self-employment earnings and no other wage income. Your SE tax base is $55,410 (92.35% of $60,000). Social Security tax comes to $6,870.84 (12.4%), well under the annual wage base, and Medicare tax comes to $1,606.89(2.9%). You're well under the Additional Medicare Tax threshold for a single filer, so no extra 0.9% applies. Your total self-employment tax is $8,477.73, of which $4,238.87 — half of the Social Security and Medicare portions — is deductible from your income at tax time.

Common mistakes

• Using gross revenue instead of net earnings: self-employment tax applies to your profit after business expenses (Schedule C), not the total amount clients paid you — using gross revenue overstates what you owe.
• Forgetting the 92.35% factor: applying 15.3% straight to your net earnings, instead of to 92.35% of them, overstates the tax by a small but real amount.
• Ignoring wages from a second job: if you also have a W-2 job, its wages count toward the same Social Security wage base and Additional Medicare Tax threshold — leaving them out can make this calculator (or your own estimate) overstate what you owe.
• Not setting aside estimated tax payments: since there's no employer withholding this for you, most self-employed people need to make quarterly estimated tax payments to the IRS to avoid an underpayment penalty — this calculator estimates the tax itself, not your payment schedule.

Frequently asked questions

What actually moves this number

Specific levers, and roughly what each one is worth. Not “save more” — the things that change the figure above by an amount you can measure.

• Separate 25-30% of every payment the day it arrives

  A different account, moved on receipt, before the money looks spendable. The first-year failure mode is owing income tax plus 15.3% self-employment tax on twelve months of profit all at once, plus an underpayment penalty on top.

• Use the prior-year safe harbor if income is lumpy

  Paying 100% of last year's total tax through estimates (110% if prior-year AGI topped $150,000) generally removes the penalty regardless of how this year turns out. It is a known number available in January, which beats forecasting.

• Track expenses like they are worth 30 cents on the dollar, because they are

  Every deductible dollar cuts self-employment tax at 15.3% and income tax at your bracket. In the 22% bracket a $1,000 expense is worth roughly $340. Mileage, home office, software, and phone are the ones most often left on the table.

• Ask a CPA about an S corp election once profit is steady

  Above roughly $50,000-$80,000 of consistent net profit, an S corporation election can reduce self-employment tax on the distribution portion. It also adds payroll, filings, and cost — which is exactly why it is a conversation, not a rule of thumb.

What this calculator does not cover

Every calculator simplifies, and the useful thing is knowing exactly where. These are the specific gaps between this estimate and your real situation:

• It calculates self-employment tax only. Federal income tax on the same earnings is separate and additional, as is state income tax.
• Business deductions must be applied before you enter net earnings. The tax is computed on profit after deductible expenses, not on gross revenue.
• It does not model an S corporation election, which changes the calculation substantially for some businesses and is worth a conversation with a CPA rather than a rule of thumb.
• Quarterly estimated payments are not scheduled here. Owing $1,000 or more generally triggers the requirement, and skipping them adds an underpayment penalty computed like interest.

For anything that turns on an exact figure, use the primary sources below or a qualified professional. How these limits are decided and disclosed is described in the editorial standards.