2026 Estimated Tax Due Dates: April 15, June 15, September 15 and January 15

Self-employed clients often ask the same question: when do I pay my estimated taxes? The IRS estimated tax FAQs answer it, and they also explain who has to pay and what to do when income is uneven. Here is a practical summary for preparers and small-business owners.

The four due dates for tax year 2026

For estimated tax purposes, the IRS divides the year into four payment periods. Each period has its own due date. For tax year 2026 (Form 1040-ES (2026)), the dates are:

• Income from Jan. 1 to March 31: due April 15, 2026
• Income from April 1 to May 31: due June 15, 2026
• Income from June 1 to Aug. 31: due September 15, 2026
• Income from Sept. 1 to Dec. 31: due January 15, 2027

If a due date falls on a Saturday, Sunday or legal holiday, the payment is on time if it is made on the next day that is not a Saturday, Sunday or legal holiday.

The IRS also notes that if you don't pay enough by the due date of each period, you may be charged a penalty, even if you are due a refund when you file your return. A client who expects a refund can still owe a penalty.

Who has to make estimated payments

Generally, a person must make estimated payments for the current year if both of these apply:

• They expect to owe at least $1,000 in tax after subtracting withholding and refundable credits.
• They expect withholding and refundable credits to be less than the smaller of 90% of the tax shown on the current year's return, or 100% of the tax shown on the prior year's return.

The 100% figure becomes 110% if adjusted gross income on the prior year's return was greater than $150,000 ($75,000 if married filing separately). The IRS adds that the prior-year return must cover all 12 months.

Special rules apply to farming and fishing income, certain household employers, certain higher-income taxpayers, taxpayers whose prior return covered less than 12 months, and nonresident aliens.

What to tell Schedule C clients

Estimated payments cover both income tax and self-employment tax. The IRS says that, generally, a taxpayer who needs to pay both can make quarterly payments or pay the full amount due on the first quarterly due date. The IRS points small-business owners who file Schedule C to Publication 334, Tax Guide for Small Business, and to Publication 505, Tax Withholding and Estimated Tax.

A client with no tax liability for the prior year may avoid the penalty. The IRS defines that as total tax of zero, or gross income below the filing threshold. Two more conditions apply: the prior year was a 12-month tax year, and the person was a U.S. citizen or resident throughout that year.

Uneven income and large gains

A sizable capital gain by itself may not create a requirement to pay estimated tax. If a client's income arrives unevenly, the IRS says they may be able to annualize it and pay, or pay more, for the quarter in which the income was received. The Annualized Estimated Tax Worksheet in Publication 505 helps calculate the payment.

A client who chooses this route must complete and attach Form 2210 to the return, using the annualized income installment method (Form 2210), to show that the uneven payments match the uneven income.

Clients with wages can also raise their withholding instead. If the right amount is withheld, they may not need to make estimated payments and may not have to file Form 2210. Voluntary payments are also allowed at any time before the return due date.

Farming, fishing and fiscal-year filers

For tax year 2026, a calendar-year taxpayer with at least two-thirds of gross income from farming or fishing (in 2025 or 2026) can pay all estimated tax by January 15, 2027. The other option is to file the 2026 Form 1040 or 1040-SR by March 1, 2027 and pay all the tax owed then. Fiscal-year taxpayers should see the special rules in Chapter 2 of Publication 505.

How to pay and how to report

Payment options include your online account, Direct Pay with a bank account, phone, and the IRS app. The IRS Make a payment page lists all options. Partners generally need Form 1040-ES because partnerships don't withhold tax from distributions.

On the personal return, report all estimated payments on Form 1040, line 26. Include any overpayment the client chose to credit from the prior-year return.

Tip for preparers: send clients a calendar with the four dates, ask about uneven income before the quarter ends, and confirm each client's prior-year total tax and adjusted gross income when checking the safe harbor.

Informational only, based on the IRS source linked above; not tax or legal advice for a specific situation.