Comprehensive Guide
Learn more in our Business & Tax Guide.
How it works
self-employment tax calculator takes your inputs and produces quarterly payment, total annual tax, self-employment tax, federal income tax, profit. Quarterly tax estimates for freelancers and solo operators: self-employment tax plus federal income on your profit. You provide 4 inputs: Self-employment income (currency, in dollars) (default: 80000 dollars); Deductible expenses (currency, in dollars) (default: 12000 dollars); Self-employment tax rate (percent, in percent) (default: 15.3 percent); Federal income rate (est.) (percent, in percent) (default: 22 percent). The calculator returns 5 outputs: Quarterly payment (the primary result); Total annual tax (a secondary output); Self-employment tax (a secondary output); Federal income tax (a supplementary figure); Profit (a supplementary figure). Business tax and finance calculations combine multiple moving parts — revenue, expenses, depreciation, tax brackets, and timing — in ways that make back-of-envelope estimates unreliable. This calculator handles the interaction of those variables precisely, so your business decisions rest on real arithmetic. The underlying formula: SE tax = profit x 15.3% (half deductible) | Federal = (profit - half SE tax) x federal% | Quarterly = total / 4 With the default values, quarterly payment is computed from the interaction of every input field — change any one of them and the result updates immediately, so you can stress-test different scenarios without re-entering the whole form. Adjust the inputs to match your real financial situation. The defaults are realistic starting points, but every person's circumstances differ — your actual income, expenses, rates, and timelines will produce a different answer. Use the tool iteratively: start with the defaults, then change one variable at a time to see which factor has the largest impact on your outcome.Formula
SE tax = profit x 15.3% (half deductible) | Federal = (profit - half SE tax) x federal% | Quarterly = total / 4
Tips
- Set aside 25-35% of every payment into a tax account before it becomes spendable money.
- Open a SEP-IRA or solo 401(k) — retirement contributions cut taxable profit dollar for dollar.
- Track expenses in real time; year-end reconstruction misses most deductions.
- Pay quarterly on schedule — the underpayment penalty is a quiet, avoidable tax.
Frequently asked questions
What is self-employment tax?
Social Security and Medicare for the self-employed, at 15.3% of profit — the combined employee and employer shares. Half of it is deductible on your income tax, and there is an income cap on the Social Security portion (the wage base, which rises annually).
When are quarterly estimated taxes due?
April 15, June 15, September 15 and January 15 of the following year. The IRS expects roughly 90% of the year's liability paid by year end or you owe interest on the gap; salaried freelancers also have the W-4 withholding option to cover it instead.
What expenses can I deduct as a freelancer?
Anything ordinary and necessary for the business: home office (the simplified $5/sq ft method or actuals), equipment, software, travel, meals with clients at 50-100%, professional fees and insurance. Keep receipts and a clean ledger — the deduction list is the difference between a healthy and a painful estimate.
How is my profit different from my income?
Income is what clients paid you; profit subtracts deductible business expenses. The SE tax and income tax both apply to profit, so the expenses line is your legal tax lever. This calculator taxes profit, not income — the reason it exists.