Quarterly tax calculator: your 2026 estimated tax payments and due dates.

How it's worked out

How quarterly estimated tax works for 2026.

Tax is paid as you earn. With no employer withholding from business profit, a seller generally pays during the year through estimated tax, which covers self-employment tax as well as income tax. The 2026 Form 1040-ES sets out when you have to pay and how much is enough.

Required for 2026 = the smaller of 90% of your 2026 tax or 100% of your 2025 tax
110% instead of 100% if your 2025 AGI was over 150,000.00 (75,000.00 married filing separately)

You generally have to pay estimated tax when you expect to owe at least 1,000.00 for 2026 after withholding and refundable credits, and your withholding and credits will come to less than that required amount. The 2025 return has to cover all 12 months. Last year's figure is the safe-harbor route: it is known today, so it does not depend on how this year's sales go.

Estimated 2026 tax = self-employment tax + Additional Medicare Tax + income tax on (net profit + wages − half of SE tax − standard deduction)

The income tax estimate uses the 2026 standard deduction, 16,100.00 single and 32,200.00 married filing jointly, and the 2026 rate schedules from 10% to 37%. It is a simple estimate: it leaves out credits, the qualified business income deduction, itemized deductions, other income and state tax, so your real figure can differ. Self-employment tax is worked out as in the self-employment tax calculator.

Each payment = to pay for 2026 ÷ 4 (the last one takes any cent left over)

For calendar-year 2026 the four payments are due April 15, 2026, June 15, 2026, September 15, 2026 and January 15, 2027. The 2026 Form 1040-ES adds that the January payment is not needed if you file your 2026 return by February 1, 2027 and pay the whole balance with it.

The sample: 85,000.00 of net profit gives 12,010.12 of self-employment tax. Income less half of that is 78,994.94; after the 16,100.00 standard deduction, 62,894.94 is taxable, and the 2026 single schedule gives 5,800.00 plus 22% of the 12,494.94 over 50,400.00, or 8,548.89. The estimate is 20,559.01, and 90% of it, 18,503.11, is four payments of about 4,625.78.

This is an estimate for planning. Farmers and fishermen, household employers and fiscal-year filers have their own rules in the form instructions, and your tax preparer confirms the amounts for your return.

Sources

1. IRS: Form 1040-ES (2026), Estimated Tax for Individuals, fetched 7 Oct 2026 — $1,000 test, 90% / 100% / 110% rules and the $150,000 AGI line, payment due dates, 2026 Tax Rate Schedules, standard deduction.
2. IRS: Estimated taxes, fetched 7 Oct 2026 — estimated tax covers self-employment tax as well as income tax.
3. IRS: Rev. Proc. 2025-32, fetched 7 Oct 2026 — 2026 rate tables for single and married filing jointly (Tables 1 and 3) and standard deduction (section .14).
4. IRS: Self-employment tax (Social Security and Medicare taxes), fetched 7 Oct 2026 — 12.4% and 2.9% parts, $400 floor.
5. Social Security Administration: Contribution and benefit base, fetched 7 Oct 2026 — 2026 wage base of $184,500.
6. IRS: Questions and answers for the Additional Medicare Tax, fetched 7 Oct 2026 — 0.9% and the $200,000 / $250,000 thresholds.