Self-employment tax calculator

How self-employment tax works

An employee and employer each pay Social Security and Medicare on wages. When you work for yourself you pay both halves, as self-employment tax: 15.3% in all, 12.4% for Social Security and 2.9% for Medicare. It applies to 92.35% of net profit, which mirrors the employer half being a business cost, and it starts once net earnings reach $400. The Social Security part stops at the $184,500 wage base, counting any W-2 wages first.

Half of the self-employment tax is then deducted from income for income tax, and most sole proprietors also get the qualified business income deduction. So the order is: profit, self-employment tax on 92.35% of it, adjusted gross income after half of that tax, taxable income after the standard deduction and QBI, then the brackets.

A worked example

A single freelancer with $60,000 of net profit and no other income has net earnings of $55,410 for self-employment tax, which comes to $8,478. Half of it, $4,239, is deducted from income, and the QBI deduction is $7,932. Federal income tax is $3,559. Together that is $12,037, or 20.1% of profit, before any state tax.

Split into four estimated payments it is about $3,009 each, due on April 15, 2026, June 15, 2026, September 15, 2026, January 15, 2027. The calculator saves those dates to your calendar as an .ics file, made in your browser.

Side income on top of a job

Side income is taxed at the top of your pay. With $180,000 of W-2 wages, $20,000 of freelance profit costs $36,763 of federal tax, against $3,025 if it were your only income. Wages near the Social Security wage base cut the self-employment tax, because Social Security is only owed once on pay up to the base, but the income tax rate on the side profit is higher.

How much to set aside

A simple habit works for most freelancers: move a fixed share of every payment into a separate account the day it arrives. In the example above, federal tax takes 20.1% of profit, so setting aside a little more than that covers the federal bill with room for state tax. Recalculate when your income changes by much, and in the spring once last year's return shows your real numbers.

The IRS safe harbor helps if income is hard to predict. Paying in at least as much as last year's total tax, spread over the four dates, avoids the underpayment penalty even if this year turns out bigger; higher earners need to pay a little more than last year's tax. The balance is then due by the April filing deadline. Business expenses lower both taxes at once, since they reduce profit before either is worked out.

What the inputs mean

• Net profit: income minus business expenses, the figure on Schedule C line 31.
• W-2 wages: pay from a job, which uses up part of the Social Security wage base and sets your income tax bracket.
• Filing status: as on your return.

Common mistakes

• Saving only for income tax. Self-employment tax is often the larger bill at modest profits.
• Using gross receipts instead of profit. Business expenses come off first, and keeping records of them is the cheapest tax saving there is.
• Paying everything in April. Missing the quarterly dates can mean an underpayment penalty even if you pay in full when you file.

Rules checked October 19, 2026. How we calculate.