The 2026 quarterly estimated tax due dates are April 15, 2026; June 15, 2026; Sept. 15, 2026; and Jan. 15, 2027. To avoid an underpayment penalty, a taxpayer generally needs to pay in (through withholding and estimated payments combined) the smaller of 90% of the current year's tax or 100% of the prior year's tax. That threshold rises to 110% if the prior year's adjusted gross income was over $150,000 ($75,000 if married filing separately). This is the safe harbor most preparers default to, since it's based on a known number (last year's return) rather than a projection.

When are the 2026 estimated tax due dates?

The four 2026 due dates are April 15, June 15, Sept. 15, and Jan. 15, 2027, each tied to the income period it covers rather than to a clean calendar quarter.

None of the 2026 due dates fall on a weekend or federal holiday, so no payment gets pushed to the next business day this cycle. If a due date ever does land on a Saturday, Sunday, or legal holiday, the payment is on time if made the next business day.

What is the safe harbor rule for estimated taxes?

By default, a taxpayer is safe from the underpayment penalty if total withholding and estimated payments equal at least 100% of the prior year's total tax (110% if prior year AGI was over $150,000, or $75,000 for married filing separately). The exception: if 90% of the current year's tax turns out to be a smaller number, that lower figure satisfies the safe harbor instead. This matters when income drops year over year.

In practice, the 100%/110%-of-last-year test is the one preparers reach for first, because it's calculable in January without waiting on current-year numbers. The 90%-of-this-year test only helps when current-year liability is going to be lower than last year's.

Who actually has to make estimated payments?

Anyone (individual, sole proprietor, partner, or S-corp shareholder) who expects to owe $1,000 or more in tax for 2026 after subtracting withholding and refundable credits generally needs to make estimated payments. This catches most self-employed taxpayers and partners receiving Schedule K-1 income, since neither has an employer withholding tax throughout the year.

Is there a different rule for farmers and fishermen?

Yes. If at least two-thirds of gross income for 2025 or 2026 comes from farming or fishing, the taxpayer has two options instead of four quarterly payments: pay the full 2026 estimated tax in one payment by Jan. 15, 2027, or skip the estimated payment entirely by filing the 2026 return and paying the full tax due by March 1, 2027.

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Sources: IRS, "Estimated Taxes" FAQ (irs.gov/faqs/estimated-tax), Page Last Reviewed 04-Dec-2025; IRS 2026 Form 1040-ES instructions; IRS, "Farmers, fishermen face March 1 tax deadline" (irs.gov/newsroom). Confirmed current for tax year 2026 via IRS.gov direct fetch, 2026-06-17.