Short answer
Individuals, including sole proprietors, partners and S corporation shareholders, generally must pay estimated tax if they expect to owe $1,000 or more for 2026 after withholding and credits. The 2026 payments are due April 15, June 15 and September 15, 2026, and January 15, 2027. You generally avoid the underpayment penalty by paying at least 90% of your 2026 tax or 100% of your 2025 tax (110% if your 2025 AGI was over $150,000).
An employee has tax taken out of every paycheck. A business owner usually doesn't, so the IRS asks for the tax in four installments during the year instead. These are estimated tax payments, often called quarterly taxes. Miss them, or pay too little, and the IRS can add a penalty even if you pay everything by April.
This guide covers the 2026 tax year, using IRS Publication 505 (2026) and the IRS estimated taxes page, linked at the end.
What are the 2026 estimated tax due dates?
| Income earned | Payment due |
|---|---|
| January 1 to March 31, 2026 | April 15, 2026 |
| April 1 to May 31, 2026 | June 15, 2026 |
| June 1 to August 31, 2026 | September 15, 2026 |
| September 1 to December 31, 2026 | January 15, 2027 |
The periods are not equal quarters, which catches people out. The second period is only two months long, and the last one runs four months.
The January payment has an exception. If you file your 2026 Form 1040 or 1040-SR by January 31, 2027, and pay the rest of the tax you owe with it, you don't need to make the January 15 payment.
Who has to make estimated tax payments?
Individuals, including sole proprietors, partners and S corporation shareholders, generally have to pay estimated tax if they expect to owe $1,000 or more when they file. Under Publication 505, that applies when you expect to owe at least $1,000 for 2026 after subtracting withholding and credits, and your withholding and credits will be less than the smaller of:
- 90% of the tax on your 2026 return, or
- 100% of the tax on your 2025 return.
Estimated tax covers more than income tax. The IRS says it is also used to pay self-employment tax and the alternative minimum tax. For many business owners, self-employment tax is a large part of the bill.
Corporations have their own rule: they generally make estimated payments if they expect to owe $500 or more when the return is filed.
A single-member LLC is taxed like a sole proprietorship by default, so its owner follows the individual rules above. Our article on sole proprietor vs. LLC explains why.
How to avoid the underpayment penalty: the safe harbors
You may owe a penalty if you didn't pay enough tax during the year through withholding and estimated payments. You generally avoid it if your 2026 payments, made on time, cover the smaller of:
| Safe harbor | What you pay during 2026 |
|---|---|
| Current year | 90% of your 2026 tax |
| Prior year | 100% of your 2025 tax |
| Prior year, higher income | 110% of your 2025 tax if your 2025 AGI was more than $150,000 ($75,000 if married filing separately) |
The prior-year safe harbor is the easier one to plan around, because you already know the number. Divide it into four and pay each part by its due date. If your income jumps during the year, you still avoid the penalty, and you pay the extra when you file.
Two smaller rules from the IRS: most people owe no penalty if the amount still due after withholding and credits is less than $1,000, and farmers and fishermen use 66 2/3% in place of 90%.
How to figure what to pay
- Start from last year. The IRS suggests using your 2025 return as a guide for your 2026 estimate.
- Estimate this year's profit. Up-to-date bookkeeping makes this a quick look at your profit and loss statement instead of a guess.
- Use the Form 1040-ES worksheet. Individuals use Form 1040-ES to figure the payments. Nonresident aliens use Form 1040-ES (NR).
- Compare with the safe harbor. Paying the safe harbor amount may be lower, or simpler, than paying on your estimate.
- Adjust during the year. If income changes a lot, refigure before the next due date.
How to pay estimated tax
- Online: through your IRS online account, IRS Direct Pay, or the IRS app.
- Businesses: through a business tax account or Direct Pay for businesses. Some business payments must still go through the Electronic Federal Tax Payment System (EFTPS).
- By mail: with a Form 1040-ES payment voucher.
Keep the confirmation for every payment. You will report the total on your 2026 return.
Common mistakes
- Waiting for the April bill. Paying everything in April can still mean a penalty for the quarters you missed.
- Forgetting self-employment tax. Estimate the income tax and the self-employment tax.
- Treating the periods as equal quarters. The June payment covers only April and May.
- Not refiguring after a big month. A large contract can push you past the safe harbor you planned for.
For every federal deadline in the coming filing season, see our list of LLC tax deadlines for 2027.
How Top Accounting Firm can help
Our tax planning service works out each quarterly payment from your actual numbers and reminds you before every due date. Combined with monthly bookkeeping, you know where you stand all year. Book a free consultation before the January 15 payment.
Frequently asked questions
When is the last 2026 estimated tax payment due?
Do I have to pay estimated taxes if I have an LLC?
What is the safe harbor for estimated taxes in 2026?
Does estimated tax include self-employment tax?
Which form do I use for estimated tax payments?
How do I pay estimated tax online?
Sources
- IRS: Publication 505 (2026), Tax Withholding and Estimated Tax
- IRS: Estimated taxes
- IRS: Form 1040-ES, Estimated Tax for Individuals
Checked against these sources on October 26, 2026. This article is general information, not tax or legal advice. Rules, fees and deadlines change, so confirm with the official source or a tax professional before you file.
