Self-Employment Tax and Quarterly Estimate Calculator
For freelancers, 1099 contractors and sole owners. Estimate your self-employment tax, federal income tax and the four quarterly payments, including the safe-harbor amount that avoids an underpayment penalty.
Enter your numbers
Suggested payment each quarter
$0
| Self-employment tax (15.3%) | |
| Social Security part (12.4%) | |
| Medicare part (2.9%) | |
| Federal income tax | |
| Additional Medicare Tax | |
| Estimated total federal tax | |
| Minus W-2 withholding | |
| Left to pay through estimates |
How we got there
| Net earnings from self-employment (92.35%) | |
| Deduction for half of self-employment tax | |
| Adjusted gross income | |
| Standard deduction | |
| QBI deduction (20%) | |
| Taxable income | |
| Top federal bracket reached |
Due dates
Estimate only. General information, not tax advice for your situation.
How the math works
- 1
Self-employment tax
Multiply profit by 92.35%. Social Security is 12.4% of that, up to the wage base ($184,500 in 2026, less any W-2 wages). Medicare is 2.9% with no limit. No self-employment tax is due if net earnings are under $400.
- 2
Income tax
Half of the self-employment tax is deducted, then the standard deduction and the 20% QBI deduction. The 2026 tax brackets apply to what is left.
- 3
Quarterly payments
To avoid an underpayment penalty, pay the smaller of 90% of this year's tax or 100% of last year's (110% if last year's adjusted gross income was over $150,000), spread over four due dates.
Single freelancer, 2026, $80,000 profit, no other income or withholding, last year's total tax $9,000.
| Self-employment tax (15.3% of $73,880) | $11,304 |
| Taxable income after deductions | $46,599 |
| Federal income tax | $5,344 |
| Estimated total tax | $16,647 |
| Quarterly payment to cover it all | $4,162 |
| Safe-harbor quarterly payment (100% of $9,000) | $2,250 |
Paying the safe-harbor amount avoids the penalty, but the rest is still due by the April filing deadline. Made-up numbers.
What it includes, and what it doesn't
- 2026 brackets and standard deduction from IRS Rev. Proc. 2025-32
- Social Security wage base and the W-2 wage offset
- Additional Medicare Tax above $200,000 ($250,000 joint)
- QBI deduction for taxable income up to $201,750 ($403,500 joint)
- Not included: credits (child tax credit and others), itemized deductions, the senior deduction, retirement contributions, self-employed health insurance, capital gains rates and state income tax
- Above the QBI threshold, the deduction isn't estimated, so the tax shown may be high
- 2027 is for planning: it uses the announced $192,300 wage base and 2026 brackets until the IRS publishes 2027 amounts
Do I have to make quarterly payments?
Generally yes, if you expect to owe $1,000 or more after withholding and credits. If you have a W-2 job, raising your withholding can cover the tax instead.
What if my income changes during the year?
Recalculate and adjust the remaining payments. If income comes in unevenly, the annualized income method (Form 2210, Schedule AI) can lower the penalty.
Is self-employment tax the same as income tax?
No. Self-employment tax is Social Security and Medicare for people who work for themselves. Income tax is separate. You can owe self-employment tax even when you owe no income tax.
When does an S-corp make sense?
An S-corp can lower self-employment tax once profit is high enough to cover a reasonable salary and the extra costs. Try the S-Corp Savings Calculator.
Sources
- IRS: Self-employment tax
- IRS: Schedule SE (Form 1040)
- IRS Publication 505: Tax withholding and estimated tax
- IRS: Estimated taxes
- IRS: 2026 inflation adjustments
- SSA: Contribution and benefit base
- IRS Topic 560: Additional Medicare Tax
Built and reviewed by Taz, U.S. tax preparer. Last reviewed November 1, 2026.
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