Federal · Tax year 2026
Extension deadline October 15, 2027.
An extension moves your filing date, not your payment date. Estimate what unpaid tax costs.
Short answer: A Form 4868 extension for your 2026 tax return gives you until Friday, October 15, 2027 to file, but any tax owed is still due Thursday, April 15, 2027. The IRS charges 0.5% of unpaid tax per month from April 15, and a late return adds 5% per month on top (4.5% once both apply).
Estimate the penalty
Result
Enter the tax you still owe and two dates, then press Estimate penalty.
The two dates
For tax year 2026, the regular due date is Thursday, April 15, 2027. The IRS says an extension gives you until October 15 to file without penalties, which for 2027 is a Friday. The extension is only for filing the return; the IRS says to make sure you pay any tax you owe by the April filing date.
Three ways to get the extension
- Pay online with an IRS payment option and check the box that the payment is for an extension. You do not file a separate form and you get a confirmation number.
- Use IRS Free File to electronically request the automatic extension; there is no income limit for extensions.
- File Form 4868 by mail, online with an IRS e-file partner or through a tax professional, estimating your tax for the year on the form.
The IRS says U.S. citizens and resident aliens living outside the country on the regular due date may get an automatic two-month extension, and disaster-area taxpayers may get more time. Other forms apply to businesses, exempt organizations and retirement plans.
What unpaid tax costs
| Penalty | Rate | Cap |
|---|---|---|
| Failure to pay | 0.5% of unpaid tax per month or part of a month, from April 15 | 25% |
| Failure to file | 5% of tax due per month or part of a month after the filing deadline | 25% |
| Both in the same month | 4.5% failure to file plus 0.5% failure to pay | Failure to file maxes out after 5 months |
| Return more than 60 days late | Minimum failure-to-file penalty is the lesser of $525 or 100% of the tax due (return due after 12/31/2025) | n/a |
An approved payment plan reduces the failure-to-pay rate to 0.25% per month if you filed on time. Interest also accrues on unpaid tax; the IRS sets that rate by quarter and this page does not model it.
Worked example (projected)
Say you owe $5,000 on April 15, 2027, request an extension, then file and pay on October 15, 2027. The return is on time, so there is no failure-to-file penalty. Failure to pay runs from April 15 for 6 months: 6 x 0.5% = 3%, or $150, plus interest. Had you not requested an extension and filed and paid on July 20, 2027, that would be 4 months late: failure to file 4 x 4.5% = 18% ($900) plus failure to pay 4 x 0.5% = 2% ($100), or $1,000 before interest. The extension is worth the form.
These amounts are projected for the 2027 filing season using the rules and the $525 minimum the IRS lists today; the IRS can change figures, so check the penalty pages below.
What this does not cover
- Interest, reasonable-cause or first-time penalty relief.
- State extensions, which have their own forms and dates.
- Penalties on amended returns, estimated-tax underpayments or business returns.
Sources
- IRS: Get an extension to file your tax return (read November 1, 2026)
- IRS: Failure to pay penalty (read November 1, 2026)
- IRS: Failure to file penalty (read November 1, 2026)
- IRS: About Form 4868 (read November 1, 2026)
Frequently asked questions
What is the extension deadline for the 2026 tax return?
October 15, 2027, a Friday, if you request an extension by the April 15, 2027 due date.
Does an extension give me more time to pay?
No. The IRS says the extension is only for filing the return and you should pay any tax you owe by the April filing date.
How do I request the extension?
Pay online and check the extension box, use IRS Free File to request it, or file Form 4868 by mail, with an e-file partner or through a tax professional.
How much is the late-payment penalty?
0.5% of the unpaid tax for each month or part of a month, up to 25%.
How much is the late-filing penalty?
5% of the tax due per month or part of a month, up to 25%. When both penalties apply in the same month the filing penalty is 4.5% and the payment penalty 0.5%.
What is the minimum late-filing penalty?
If a return due after December 31, 2025 is more than 60 days late, the minimum is the lesser of $525 or 100% of the tax due, per the IRS table read November 1, 2026.
General information, not tax advice
This page estimates penalties from the IRS rules named in Sources. The dollar figures are projections for the 2027 filing season, not a bill, and exclude interest. It is an unofficial guide and is not run by the IRS. Nothing you enter is transmitted. Confirm your situation with the IRS or a tax professional.