Failure-to-File Penalty: 5% Per Month Up to 25% — Plus the 60-Day Minimum

The failure-to-file penalty (§6651(a)(1)) is the most expensive common penalty in the individual tax system: 5% of your net tax due for every month — or part of a month — your return is late, up to 25%. Filing one day into a new month costs the same as filing on its last day, and for small balances filed very late, a statutory minimum penalty can exceed the percentage math entirely. This page owns the mechanics: the rate, the base it’s charged on, the three separate clocks that govern it, and the minimum penalty most explainers skip. For the penalty that runs alongside it, see failure to pay — and to model your own dates, the IRS penalty calculator.

General tax information, not tax or legal advice. Dollar minimums below are for returns required to be filed in 2026 and are inflation-adjusted annually.

The rate and the base

• Rate: 5% per month or part of a month, maximum 25% (five months to the cap).
• Base: the tax required to be shown on the return, minus what you already paid by the due date — withholding, estimated payments — and minus refundable credits (IRS failure-to-file guidance). The IRS penalizes the net unpaid amount, not your gross tax bill.
• No tax due, no penalty. If you’re owed a refund, there is no failure-to-file penalty no matter how late you file (the refund itself is what you lose if you wait past three years — a different rule).
• Interest also accrues on the penalty itself, from the return’s due date.

Accrual on a $10,000 net balance (percentage math only)

One interaction to know exists before you rely on this table alone: in months when the failure-to-pay penalty also runs, the overlap rule trims the failure-to-file slice to 4.5% for those months — the full stacking table lives on the failure-to-pay page, because late filing and late paying usually arrive together.

The 60-day minimum penalty — where small balances get crushed

If your return is more than 60 days late, the penalty is not less than the lesser of $525 or 100% of the tax required to be shown (Topic No. 653). The $525 figure applies to returns required to be filed in 2026; it was $510 for returns required to be filed in 2025, and it adjusts for inflation each year. Watch what that does to small balances:

• $800 of tax, filed 3 months late. Percentage math: 15% × $800 = $120. Minimum: lesser of $525 or $800 → $525. You owe $525 — more than four times the percentage result.
• $400 of tax, filed 4 months late. Percentage math: 20% × $400 = $80. Minimum: lesser of $525 or 100% of the tax ($400) → $400 — the penalty equals the entire tax.

And one more wrinkle: when the minimum penalty applies, the 4.5% overlap reduction described above does not reduce it. For very late small returns, the minimum is the penalty — which is also why first-time abatement (which expressly covers this penalty) and reasonable cause matter so much on these notices.

Three clocks, three different triggers

1. The filing clock starts at the due date as extended — a valid extension moves this deadline (typically to October 15), and the 5% runs from the extended date.
2. The 60-day trigger is counted from that same (extended) due date; crossing it switches on the minimum penalty.
3. The payment clock never moves. An extension gives you more time to file, never more time to pay — the failure-to-pay penalty runs from the original April due date whether or not you extended. This is the single most expensive misunderstanding in the penalty system: an extended return filed in October with the tax unpaid since April carries five-plus months of payment penalty even though the filing penalty is zero.

The fraud end of the scale (one line, for completeness)

If the failure to file is fraudulent, the rate is 15% per month up to 75% instead — a different penalty posture entirely, and professional-help territory.

Getting out from under it

This penalty is covered by First-Time Abate (now transitioning to the automatic AEP — the hub explains which regime your period falls under) and by reasonable cause when the failure has a qualifying explanation. Interest on the penalty adjusts if the penalty is abated; interest on the tax does not. If a failure-to-file notice is left to age into enforced collection, the route from notice to levy is the one mapped in our wage garnishment cluster — penalties are cheapest the month they’re addressed.

Frequently asked questions

What is the penalty for filing taxes late? For most individuals it’s the failure-to-file penalty: 5% of the net tax due per month or part of a month, up to 25% (§6651(a)(1)). If the return is more than 60 days late, a minimum applies — the lesser of $525 (returns required to be filed in 2026) or 100% of the tax — which can be larger than the percentage calculation on small balances.

How is the failure-to-file penalty calculated? Multiply the tax required to be shown on the return — reduced by payments made by the due date (withholding, estimates) and refundable credits — by 5% for each month or part-month of lateness, stopping at 25%. Then compare against the 60-day minimum if the return was more than 60 days late and take the larger figure. The penalty calculator runs both computations.

What happens if I file 1 day late? A part of a month counts as a full month: filing one day late triggers the full first 5%. The one consolation is that the 60-day minimum doesn’t apply yet — a return filed within 60 days is penalized on the percentage math alone.

Is there a penalty for filing late if I don’t owe tax? No. The penalty is a percentage of net tax due, so a refund return filed late carries no failure-to-file penalty. (Waiting too long still has a cost: refunds generally can’t be claimed more than three years after the due date — but that’s forfeiture of your money, not a penalty.)

Does an extension prevent the failure-to-file penalty? Yes for filing — a valid extension moves the filing deadline, and the 5% runs only from the extended due date — provided you actually file by then. But the extension does not move the payment deadline: the failure-to-pay penalty accrues from the original due date on any unpaid balance. File the extension and pay what you can by April.

General tax information, not tax or legal advice. Sources: IRC §6651(a)(1) and (c); IRS “Failure to File Penalty” page (rate, base, credits); IRS Topic No. 653 (60-day minimum — lesser of $525 for returns required to be filed in 2026, or 100% of the tax); Taxpayer Advocate Service materials (fraudulent-filing rate). Currency verified 2026-10-23.