Needing more time to file is common, and the IRS makes the first step easy. But the extension solves only half the problem: it gives you time to file, not time to pay. Mixing the two up is the most expensive mistake people make with Form 4868.
This guide covers the three ways to request an extension, what you need to e-file, how long you get, and the penalty arithmetic with a worked example. It follows IRS Topic 304, the Form 4868 instructions and IRS Topic 653.
| Method | How it works |
|---|---|
| Pay and mark it as an extension | Pay all or part of your estimated income tax due and indicate the payment is for an extension of time to file your return, using IRS Direct Pay, your online account, EFTPS, or a debit or credit card or digital wallet. You get a confirmation number. |
| E-file Form 4868 | E-file Form 4868, Application for Automatic Extension of Time To File U.S. Individual Income Tax Return, with your computer or through a tax professional who uses e-file. Several companies offer free filing of Form 4868 through Free File. |
| Paper Form 4868 | File a paper Form 4868. Fiscal-year taxpayers may request extensions only by filing a paper Form 4868. |
If you e-file Form 4868, have a copy of your prior year's return: you will be asked for your prior-year adjusted gross income (AGI) for verification, and once you file you receive an electronic acknowledgement that the IRS has accepted it. Keep it.
The IRS generally cannot extend the due date of a return by more than 6 months, which is October 15, 2026 for most calendar-year taxpayers in the 2025 cycle (Form 4868 instructions). For 2026 returns the same six-month rule gives Friday, October 15, 2027; the IRS's draft 2026 Form 4868 (not yet final) says the same. See our 2027 filing deadline guide for all the dates.
To qualify for the extension you must properly estimate your tax liability using the information available to you, enter your total tax liability on line 4 of Form 4868, and file the form by the due date of your return. You are not required to pay the estimated tax with it, but see the next section.
U.S. citizens and residents who are "out of the country" on the due date get two extra months (generally until June 15) automatically. The IRS defines this as living outside the United States and Puerto Rico with your main place of work outside them, or being in military or naval service on duty outside them. You can request an additional 4 months by filing Form 4868 and checking the box on line 8. The additional 4 months is not an extension of time to pay, and interest still runs on tax paid after April 15.
An extension of time to file is not an extension of time to pay. Tax unpaid after the April due date accrues interest, and the failure-to-pay penalty is one-half of one percent for each month or part of a month, up to a maximum of 25%.
The Form 4868 instructions say the late-payment penalty will not be charged if you can show reasonable cause, and that you are considered to have reasonable cause for the period of the automatic extension if both of these are met: (1) at least 90% of the total tax on your return is paid on or before the original due date through withholding, estimated tax payments or payments made with Form 4868, and (2) the remaining balance is paid with your return. Attach a statement explaining the reason to your return, not to Form 4868.
You expect to owe $4,000 but cannot finish your return by April 15. If you pay nothing and file the extension, the failure-to-pay penalty is 0.5% a month: six months to October 15 is $120.00 (0.5% x 6 x $4,000), plus interest. If you pay the $4,000 with the extension request in April, no failure-to-pay penalty builds on that amount. If you do not request an extension and file late, the failure-to-file penalty is 5% a month, up to 25%, which is far larger.
IRS Topic no. 304: Extensions of time to file, IRS Form 4868 and instructions, IRS Topic no. 653.