Failure to File vs. Failure to Pay: IRC Section 6651 Penalties

The difference between the failure-to-file and failure-to-pay penalty comes down to a factor of ten. Under IRC Section 6651, missing the filing deadline costs 5% of your unpaid tax every month, while filing on time but owing a balance costs 0.5% per month.¹ Both cap at 25% of what you owe, but the filing penalty gets there in five months and the payment penalty takes more than four years. If you can’t do both by April 15, file anyway. Not filing is the expensive mistake.

The Failure-to-File Penalty

If your federal return isn’t in by the deadline (April 15, 2026, for most individuals), the IRS adds 5% of your unpaid tax for every month or partial month it’s late.¹ One day into a new month counts as a full month. The charge stops growing at 25%, which happens after five months.

A separate rule catches people with small balances. If your return is more than 60 days late, a minimum penalty applies. For returns due after December 31, 2025, that minimum is $525 or 100% of the tax you owe, whichever is less.² Owe $200, file 61 days late, and the penalty wipes out the whole $200.

The penalty is calculated on unpaid tax, not on your full liability. Withholding and estimated payments already made reduce the base. If you’re actually owed a refund, the failure-to-file penalty is zero because there’s nothing unpaid to charge it against. You still need to file within three years to claim the refund itself.

The Failure-to-Pay Penalty

Filing on time but not paying the full balance triggers a separate 0.5%-per-month charge on the unpaid amount, also capped at 25%.¹ Reaching the ceiling takes 50 months. The penalty runs on the tax shown on the return you filed, starting the day after the payment deadline.³

On a $10,000 balance, the failure-to-pay penalty is $50 a month. The failure-to-file penalty on the same balance is $500 a month. That gap is the whole reason tax professionals repeat the same advice every spring: file on time, even if you can’t pay.

Reduced Rate With a Payment Plan

File your return on time and get an approved IRS installment agreement in place, and the monthly rate drops from 0.5% to 0.25%.⁴ Half off, for as long as the plan holds. The reduction only applies if the return was filed by its due date. Filing on time keeps unlocking better options.

Higher Rate After a Levy Notice

The rate can also move the other way. Once the IRS issues a final notice of intent to seize your property and 10 days pass without payment, the monthly rate doubles to 1%.⁵ By that stage of collections the IRS has usually sent several letters. The higher rate is designed to push action before actual levies land on wages or bank accounts.

When Both Penalties Run at the Same Time

Skip the return and skip the payment, and both penalties apply, but the law blocks pure stacking. In any month where both are running, the failure-to-file penalty is reduced by the failure-to-pay amount.¹ The filing side drops from 5% to 4.5%, the payment side stays at 0.5%, and the combined rate lands at 5% per month.

Do the math over time. For the first five months, the combined charge runs 5% monthly and reaches 25%. At that point the failure-to-file penalty has hit its ceiling. The failure-to-pay penalty has only accumulated 2.5% by then, so it keeps going at 0.5% per month until it also caps at 25%. Someone who never files and never pays maxes out at 47.5% of the unpaid tax.⁶ Interest is on top of that.

What an Extension Does and Doesn’t Do

Filing Form 4868 pushes your filing deadline to October 15. File by then and the failure-to-file penalty doesn’t apply.² What the extension doesn’t do is move your payment deadline. Any balance is still due April 15, and the failure-to-pay penalty starts running on that date if you owe.

There’s a narrow safe harbor. Pay at least 90% of your actual liability by the original April deadline and cover the rest by the extended due date, and the failure-to-pay penalty is waived entirely.⁶ If you’re close to your number but not certain, overpaying slightly by April protects you.

Interest Runs on Top of Penalties

Interest and penalties are separate charges. The IRS compounds interest daily on the unpaid tax and on the penalties themselves, so each day’s interest is calculated on the previous day’s total. The rate is set quarterly at the federal short-term rate plus three percentage points. For the first quarter of 2026 the rate is 7%, and for the second quarter it drops to 6%.⁷

Start dates differ. Interest on unpaid tax runs from the original return due date. Interest on the failure-to-pay penalty runs from when the IRS assesses or bills it. Interest on the failure-to-file penalty runs from the return due date, or from the extended due date if you filed for an extension.⁸ Unlike penalties, interest generally can’t be waived. It stops only when the balance is paid.

Getting Penalties Removed

Both penalties can be abated. Two paths do most of the work.

First Time Abate

If you’ve had a clean three-year compliance history, the IRS will remove these penalties on request. You need to have filed all required returns for the three tax years before the penalty year, had no penalties during those years (or had any prior penalties removed for reasons other than First Time Abate), and be current on filing even if the tax isn’t fully paid.⁹ For a reliable taxpayer who hit one bad year, this is the straightforward option. Call the number on your IRS notice and it can often be handled on the phone, no paperwork.¹⁰

Reasonable Cause

If First Time Abate doesn’t apply, you can still get relief by showing a legitimate reason for the failure and that you exercised ordinary care. Situations the IRS considers include:

Serious illness or death of the taxpayer or an immediate family member
Natural disasters or fires that destroyed records or blocked filing
Inability to obtain records despite reasonable efforts
System failures that prevented timely electronic filing or payment

Some reasons rarely work on their own: not knowing about the deadline, an honest math mistake, or a cash shortage.¹¹ Documentation matters. Hospital records, police reports, or correspondence showing what you tried can decide the case.

How to Ask

Start by calling the toll-free number on your notice. Many requests, especially First Time Abate, get approved on the call. If the representative can’t resolve it, submit Form 843, Claim for Refund and Request for Abatement. Include the IRC section for the penalty (listed on your notice), an explanation of why you qualify, and any supporting documents.¹⁰

1
Office of the Law Revision Counsel. 26 USC 6651 – Failure to File Tax Return or to Pay Tax
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Internal Revenue Service. Failure to File Penalty
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Internal Revenue Service. IRM 20.1.2 Failure to File/Failure to Pay Penalties
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Internal Revenue Service. Failure to Pay Penalty
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Office of the Law Revision Counsel. 26 U.S. Code 6651 – Failure to File Tax Return or to Pay Tax
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Internal Revenue Service. Get the Facts About Late Filing and Late Payment Penalties
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Internal Revenue Service. Quarterly Interest Rates
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Internal Revenue Service. Interest
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Internal Revenue Service. Administrative Penalty Relief
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Internal Revenue Service. Penalty Relief
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Internal Revenue Service. Penalty Relief for Reasonable Cause