A tax extension gives you until October 15 to file, but it does not extend your payment deadline

If you file Form 4868 with the IRS before April 15, you get an automatic six-month extension to file your return. That means your new filing deadline is October 15. However, the extension to file is not an extension to pay: taxes owed are still due on April 15, regardless of when you file. If you do not pay by April 15, you will owe interest and penalties on the unpaid amount, even if you file on time under the extension.

The extension is automatic when you file Form 4868 before the original April 15 deadline. You do not need approval from the IRS. If you miss April 15 entirely, you can still file Form 4868 late, but the IRS will treat it as a request rather than an automatic grant, and penalties may apply.

Key Takeaways

  • Filing an extension moves your return deadline from April 15 to October 15, but does not change when taxes are due.
  • You must file Form 4868 before April 15 to receive the automatic six-month extension.
  • If you owe taxes, you should pay as much as you can by April 15 to avoid interest and penalties on the unpaid balance.
  • Interest accrues daily on any taxes not paid by April 15, even if you file your return in October.

How to request an extension before April 15

File Form 4868 (Application for Automatic Extension of Time To File U.S. Individual Income Tax Return) with the IRS. You can file it electronically through tax software, by mail, or by phone. Most tax software will walk you through it as part of the filing process. If you file electronically, you get confirmation immediately. If you mail it, send it to the address listed on the form for your state.

You do not need to provide a reason for the extension. The IRS grants it automatically when you file the form before April 15. If you are unsure whether you owe taxes, you can estimate the amount on Form 4868 and pay that estimate by April 15. If you overpay, the IRS will refund the difference when you file your actual return.

What happens if you file Form 4868 after April 15

If you miss the April 15 deadline and file Form 4868 late, the IRS treats it as a request for relief rather than an automatic grant. You may still receive the extension, but you will face a failure-to-file penalty on top of any taxes owed. The penalty is usually 5 percent of unpaid taxes for each month the return is late, up to 25 percent total.

The failure-to-file penalty is separate from the failure-to-pay penalty. If you owe taxes and do not pay by April 15, you owe a failure-to-pay penalty of 0.5 percent per month (up to 25 percent) plus interest. Filing late makes both penalties apply. The sooner you file and pay, the lower your total penalty will be.

Interest and penalties that accrue between April 15 and October 15

Interest on unpaid taxes starts accruing on April 16 and continues daily until you pay. The IRS sets the interest rate quarterly; it is currently 8 percent per year, but this changes. Interest compounds daily and cannot be waived, even if you have a valid reason for not paying on time.

If you file your return on October 15 but still owe taxes, interest will have been building for six months. The longer you wait to pay, the more interest you owe. Paying as much as possible by April 15 reduces the amount subject to interest for those six months.

When October 15 arrives: your final filing deadline

October 15 is the last day to file your return under the extension. If you do not file by October 15, you will face a failure-to-file penalty on top of any taxes owed. The penalty increases the longer the return is late. If you need more time after October 15, you cannot request another extension; you must file and pay whatever you owe by that date.

If you know you cannot meet October 15, file your return anyway and pay what you can. Filing stops the failure-to-file penalty from growing. You can then work with the IRS on a payment plan for any remaining balance.

Payment plans if you cannot pay by April 15

If you owe taxes but cannot pay the full amount by April 15, you can set up a payment plan with the IRS. Short-term plans (120 days or less) have no setup fee. Long-term installment agreements have a setup fee that varies depending on how you set it up: $31 to $225 depending on the method. Interest and penalties continue to accrue on the unpaid balance until you pay in full.

You can request a payment plan online through IRS.gov, by phone at 1-800-829-1040, or by mail. Setting up a plan before April 15 shows the IRS you intend to pay, which can reduce penalties in some cases. The plan does not stop interest from accruing, but it prevents additional failure-to-pay penalties as long as you make your scheduled payments on time.

What to do if you filed an extension but cannot file by October 15

File your return anyway, even if it is late. Filing stops the failure-to-file penalty from growing at 5 percent per month. Once you file, only the failure-to-pay penalty applies (0.5 percent per month), which is lower. Pay as much as you can at the time you file.

After you file, contact the IRS to set up a payment plan for any remaining balance. You can call 1-800-829-1040 or set up a plan online. The longer you wait to file after October 15, the higher your total penalties will be, so filing immediately is important even if you cannot pay the full amount.

Frequently Asked Questions

Does filing an extension mean I do not have to pay taxes by April 15?

No. The extension only moves your filing deadline to October 15. Taxes owed are still due April 15. If you do not pay by April 15, you owe interest and penalties on the unpaid amount, even if you file your return in October under the extension.

What if I file Form 4868 but then do not file my actual return by October 15?

You will face a failure-to-file penalty. The penalty is 5 percent of unpaid taxes per month, up to 25 percent total. Filing your return even one day late triggers this penalty. If you cannot meet October 15, file anyway to stop the penalty from growing further.

Can I get another extension if I cannot file by October 15?

No. The six-month extension is the only automatic extension available. October 15 is your final deadline. If you cannot file by then, file anyway and set up a payment plan with the IRS for any taxes owed. Filing late is better than not filing at all.

How much interest will I owe if I do not pay by April 15?

Interest accrues daily at a rate set by the IRS each quarter. The current rate is 8 percent per year, but this changes. Interest compounds daily and cannot be waived. The exact amount depends on how much you owe and how long you wait to pay.

Can I set up a payment plan if I file an extension?

Yes. You can set up a payment plan before or after April 15. Short-term plans (120 days or less) have no setup fee. Long-term installment agreements have a setup fee of $31 to $225. Interest and penalties continue to accrue on the unpaid balance until you pay in full.