I missed the tax deadline — what happens now?

The short answer

If you missed the deadline for a required federal income tax return — this year's, or one from last year or earlier that you didn't file — file it as soon as you can — even if you cannot pay the full amount. Penalties and interest are generally based on what you owe and how long it stays unfiled or unpaid, so acting sooner limits them. If you are owed a refund instead, filing late can still matter, because refund claims expire.

This guide covers federal income tax returns. A late FBAR or a late Form 3520 has its own rules — see I forgot to file an FBAR and I filed Form 3520 late.

Filing late and paying late are different penalties

When both penalties apply in the same month, IRS rules reduce the combined monthly amount — you do not simply add 5% and 0.5% together. Interest can also accrue on unpaid tax, separately from the penalties.

Why filing now matters even if you cannot pay

The failure-to-file penalty is generally much larger per month than the failure-to-pay penalty. Filing stops the larger penalty from growing; you can then deal with the balance through an IRS payment option. See I can't pay my tax bill — what are my options?

If you do not owe anything

The percentage-based failure-to-file penalty is figured on unpaid tax, so it works differently when there is no balance due. That does not mean there can never be a consequence. If you are owed a refund, IRS guidance generally gives you a 3-year window to claim it from a past-due return; after that, the refund can be lost. A return that was required still needs to be filed.

If you do not file at all

The IRS may eventually prepare a substitute return for you and propose an assessment based on the information it has. A substitute return may not include deductions or credits you are entitled to. Even then, the IRS says it is in your best interest to file your own return.

Penalty relief: what changed in 2026

For years, the main administrative relief for a first penalty was First Time Abate, which taxpayers with a good compliance history could request. The IRS began phasing in the Automatic Exemption from Penalty (AEP) in 2026. AEP applies to eligible original returns beginning with tax year 2025 and to eligible 2026 quarterly returns, and the IRS applies it automatically — without a separate request — when the taxpayer meets its eligibility requirements, including a history of timely filing and payment in prior years. During the transition, First Time Abate may still apply to certain returns. For eligible original returns with original due dates on or after January 1, 2027, AEP replaces First Time Abate.

Keep its limits in mind: not every taxpayer, return, or penalty qualifies; AEP is relief from certain penalties, not from the tax itself; and interest on unpaid tax can still apply. Check the IRS AEP and administrative penalty relief pages for how it applies to your return.

Separately, the IRS penalty pages describe relief when you can show reasonable cause for filing or paying late.

Example

Sam did not file his return by the deadline and owes $3,000. Each month he waits, the failure-to-file penalty grows on the unpaid tax, along with the failure-to-pay penalty and interest. He files as soon as he can, pays $1,000 with the return, and sets up a payment option for the rest — which stops the failure-to-file penalty from growing further while the remaining balance is paid down.

Before you file

• Confirm the return was actually required — see Do I need to file a U.S. tax return?
• Gather your W-2s, 1099s, and other records for that year. If you are missing them, the IRS can provide wage and income information.
• Use the tax forms and instructions for the year you are filing, not the current year.
• If you have received IRS letters about the unfiled return, respond to them — see I received an IRS letter.