Self-Employment Tax Calculator

Two taxes, not one. Self-employment tax at 15.3% covers both halves of Social Security and Medicare, and it is charged on 92.35% of your net profit. Federal income tax then applies at your ordinary rates, and state income tax on top unless you are in one of the nine states that tax no wage income. On $80,000 of net profit a single filer in a no-income-tax state owes about $18,830 in total — 23.5% — of which $11,304 is self-employment tax.

Because you are both the employer and the employee. An employee pays 6.2% Social Security and 1.45% Medicare, and the employer quietly matches it. When you work for yourself there is no employer to match, so you owe both halves: 12.4% plus 2.9%. Two adjustments soften it — the tax applies to only 92.35% of profit, and half of what you pay is deductible against income tax.

Work from net profit, not from what you invoice. On the figures above, total tax is 23.5% of profit, so a common rule of 25% to 30% of profit is about right at moderate income and too low once you clear roughly $100,000 or work in a high-tax state. Set the calculator to your own numbers rather than using a rule of thumb: the spread between states on identical profit is wide, and expenses move it more than anything else.

Self-employment tax is charged on 92.35% of net profit rather than all of it. The purpose is symmetry with employees: an employer's half of FICA is a deductible business expense, so the law reduces the base by roughly the same proportion for the self-employed. On $80,000 of profit the base becomes $73,880, which is what the 15.3% is applied to.

Yes, and it happens automatically on the return. Half of the Social Security and Medicare portion is an above-the-line deduction against income tax — $5,652 on $80,000 of profit. It reduces your income tax, not the self-employment tax itself, and you get it whether or not you itemise. The calculator applies it before working out federal and state income tax.

Yes on the self-employment profit, but the day job uses up the Social Security wage base first, which can cut the bill sharply. Social Security stops at $184,500 of combined earnings for 2026; Medicare has no ceiling. On $80,000 of profit alongside $100,000 of W-2 wages, self-employment tax falls to about $11,304 against $11,304 with no wages at all. Enter your W-2 figure above to see it.

15 April, 15 June, 15 September and 15 January of the following year, shifting to the next business day when one falls at a weekend. Nobody withholds tax from a 1099 payment, so these instalments are how the pay-as-you-go system reaches the self-employed. Underpaying can bring a penalty calculated like interest on the shortfall. On the example above each instalment is about $4,708.

On profit. Deductible business expenses come off first: equipment, software, mileage, a qualifying home office, professional insurance, half of a business meal, and so on. That is why tracking expenses matters more for the self-employed than almost anything else — every deductible dollar removes both income tax and 15.3% self-employment tax. Below $400 of net earnings, self-employment tax is not owed at all.

On the same gross figure, yes, because you carry both halves of FICA rather than one. But the comparison is rarely like for like: 1099 income is reduced by business expenses first, while a W-2 salary is taxed from the first dollar with no equivalent. That is the reason contract rates are normally quoted well above the salary they replace. Compare properly by putting the salary through the paycheck calculator and the contract through this one.