Self-employment tax and quarterly estimated tax calculator

Calculate your self-employment tax and quarterly payment

Enter your net self-employment income (your Schedule C profit, or your share of partnership self-employment earnings), your filing status, and any W-2 Social Security wages you have already earned this year from a separate job (a W-2 job uses up part of the Social Security wage base first, which lowers the Social Security portion of your SE tax).

2026 ESTIMATE. Federal only, state income tax is not included (see the state-tax section below). Uses the 2026 Social Security wage base ($184,500, SSA), the 92.35% and 15.3% SE tax factors (IRS Schedule SE), and the 2026 federal brackets and standard deduction (IRS Revenue Procedure 2025-32). Assumes the standard deduction and no other income, credits, deductions, or self-employment retirement contributions, all of which would change your real bill.

Why do the self-employed owe self-employment tax?

Self-employment (SE) tax exists because Social Security and Medicare are normally funded by a 15.3% tax split evenly between an employer and an employee: 7.65% comes out of your paycheck, and your employer quietly pays a matching 7.65% on top. When you work for yourself, there is no employer to pay that other half, so the IRS collects the full 15.3% from you directly. It is separate from, and in addition to, your regular federal income tax. For the full explanation of who owes it and why, see self-employment tax.

How do the 15.3% and 92.35% actually work?

You do not pay 15.3% on your full net profit. Schedule SE first multiplies your net profit by 92.35%, which approximates the employer-side payroll tax a company would have paid before taxing your wages, so you are not taxed on a slice a W-2 employee never sees. The 15.3% then applies to that smaller figure, split into two pieces that behave differently:

• 12.4% Social Security, capped at the annual Social Security wage base ($184,500 for 2026). Any W-2 Social Security wages you already earned this year count against that cap first, which is what the optional W-2 field in the calculator adjusts for.
• 2.9% Medicare, with no cap at all. Every dollar of your adjusted net earnings is subject to it, no matter how high your income runs.

High earners also owe an extra 0.9% Additional Medicare Tax on combined wages and self-employment income above $200,000 (single) or $250,000 (married filing jointly). The calculator applies this automatically once your numbers cross the threshold.

What is the deductible half of self-employment tax?

You can deduct half of your Social Security and Medicare SE tax as an adjustment to income, the way an employer's matching payroll tax would never have been counted as your personal income in the first place. That deduction lowers the income subject to federal income tax, which is why it is subtracted before the bracket math runs in step (d) above. It does not reduce the self-employment tax itself, only the income tax layered on top. The 0.9% Additional Medicare Tax is never part of this deduction.

How is my federal income tax estimated on top of that?

After subtracting the deductible half of SE tax and the standard deduction from your net self-employment income, what is left is run through the ordinary 2026 federal brackets, 10% through 37%, the same marginal brackets that apply to wages. See the full 2026 bracket table by filing status for how those thresholds work and why only the income inside each bracket gets that bracket's rate. This calculator assumes the standard deduction and no other income, credits, or adjustments, so it is a starting estimate, not a substitute for actually filing.

Why are estimated taxes paid quarterly instead of once a year?

The US tax system is pay-as-you-go. A W-2 employee's taxes get withheld automatically from every paycheck, so the IRS collects steadily through the year. Self-employment income has no employer withholding anything, so the IRS requires self-employed people (generally anyone who expects to owe $1,000 or more for the year after withholding and credits) to send in estimated payments four times a year instead. Paying quarterly is what keeps you from owing an underpayment penalty when you file, and it also spreads a large tax bill into smaller, more manageable pieces rather than one lump sum in April.

When are the 2026 quarterly estimated tax due dates?

Each 2026 estimated tax payment covers a period of the year and is due on a fixed date, not the 15th of every third month:

Source: IRS Form 1040-ES instructions and Publication 505. Due dates shift to the next business day only when the 15th falls on a weekend or legal holiday; none of the 2026 dates do.

Notice the periods are not even thirds or quarters of the calendar year: the second period is only two months and the fourth is four. That uneven spacing comes straight from the IRS's own payment-period schedule, so budget for it rather than assuming every payment is exactly three months of income.

You can pay online through IRS Direct Pay or the Electronic Federal Tax Payment System (EFTPS), by mail with the payment voucher on Form 1040-ES, or, for many filers, through a tax professional's software. Paying the same amount as this calculator's quarterly figure each period, adjusted if your income changes significantly, is the simplest way to stay current.

Does this calculator include state tax?

No. This page is a 2026 federal ESTIMATE only. Self-employment tax itself is a federal-only tax (it funds Social Security and Medicare, both federal programs), but your income tax bill also depends on your state, and most states with an income tax expect their own quarterly estimated payments on a similar schedule. Check state income tax rates and rules for your state's brackets and its own estimated-payment requirements before you set your quarterly amount.

What if I also contribute to a retirement account?

A self-employed retirement contribution, most notably to a Solo 401(k), is calculated from the same net self-employment earnings this calculator starts from, and it further reduces your taxable income beyond the standard deduction used here. If you plan to make one, treat this calculator's income-tax and total-tax figures as a ceiling: a retirement contribution can only lower them, never raise them.

The flat truth: two taxes, one combined quarterly number

Self-employment tax and income tax are two separate calculations stacked on top of each other, and the quarterly estimated payment is just the sum of both, divided by four. The SE tax piece is mechanical: 92.35% of net profit, then 15.3% (minus anything above the Social Security cap), with no deductions or credits to soften it. The income tax piece is the one that actually responds to your situation: filing status, deductions, other income, and retirement contributions all move it. Recalculate whenever your net income changes meaningfully during the year rather than waiting until you file, since a large swing can turn a routine quarterly payment into an underpayment penalty or an unnecessary overpayment.