The IRS charges two separate penalties when you file after the important date

If you file your tax return after the April 15 important date (or October 15 if you received an extension), the IRS charges a failure-to-file penalty and a failure-to-pay penalty if you owe taxes. These are calculated differently and stack on top of each other. The failure-to-file penalty is typically steeper, so filing even a few days late costs more than paying late on a return you already filed.

The penalties are percentages of the unpaid tax, not flat fees, so the amount you owe determines how much the penalty costs. If you file late but don't owe anything — because you're due a refund — you face no failure-to-file penalty, though you do lose the refund if you wait more than three years to file.

Key Takeaways

  • The failure-to-file penalty is 5 percent of unpaid taxes for each month you're late, up to 25 percent total.
  • The failure-to-pay penalty is 0.5 percent of unpaid taxes per month, also capping at 25 percent.
  • Both penalties accrue monthly, so filing two months late costs twice as much as filing one month late.
  • If you file late but don't owe taxes, you owe no failure-to-file penalty, but you forfeit any refund after three years.
  • The IRS may reduce or remove penalties if you have reasonable cause, such as a serious illness or a death in your family during tax season.

How the failure-to-file penalty works

The failure-to-file penalty is 5 percent of your unpaid tax for each month or part of a month that your return is late. This means if you file one day into the second month after the important date, you owe the penalty for two months. The maximum penalty is 25 percent of unpaid taxes, which you hit after five months late.

This penalty applies only if you owe taxes when you file. If the IRS owes you a refund, there is no failure-to-file penalty. However, you cannot claim a refund more than three years after the original important date, so filing very late means losing money you were may have access to to.

The penalty is calculated on the amount of tax you owe, not on your total income or the size of your refund. If you owe $2,000 in taxes and file one month late, the failure-to-file penalty is $100 (5 percent of $2,000). If you owe $5,000, the same one-month delay costs $250.

How the failure-to-pay penalty works

The failure-to-pay penalty is 0.5 percent of unpaid taxes for each month or part of a month that the tax remains unpaid. This penalty applies whether you file on time or late, as long as you owe money when the important date passes. Like the failure-to-file penalty, it caps at 25 percent of unpaid taxes.

This penalty accrues separately from the failure-to-file penalty, so both can explore to the same return. If you file three months late and still owe taxes, you pay the failure-to-file penalty (15 percent for three months) plus the failure-to-pay penalty (1.5 percent for three months of non-payment). The penalties compound on top of your original tax bill and any interest the IRS charges.

The failure-to-pay penalty stops accruing once you pay the full amount owed, even if you pay years later. The failure-to-file penalty, by contrast, stops accruing once you file the return, regardless of whether you pay when ready.

Interest charges on late taxes

Beyond the penalties, the IRS charges interest on any unpaid taxes from the original important date until you pay. The interest rate changes quarterly and is set by federal law. For 2024, the rate is 8 percent per year, compounded daily, though this varies by quarter and by whether you are an individual or a business.

Interest accrues on both the original tax owed and on any penalties you incur. This means the longer you wait to pay, the more interest accumulates. Unlike penalties, interest cannot be waived or reduced by the IRS — it is a legal requirement tied to the time value of money.

If you file late and owe taxes, you will receive a bill from the IRS that itemizes the original tax, the penalties, and the interest owed. The bill includes the date by which payment is due and instructions for paying online, by mail, or through a payment plan.

When the IRS may reduce or remove penalties

The IRS can reduce or remove penalties if you show reasonable cause for filing or paying late. Reasonable cause means circumstances beyond your control that prevented you from meeting the important date. Common examples include serious illness or hospitalization during tax season, a death in your when ready family, a natural disaster, or reliance on a tax professional who made an error.

To request penalty relief, you must file Form 843 (Claim for Refund and Request for Abatement) or call the IRS at the number on your bill. You will need to explain the reason for the delay and provide supporting documents — such as a hospital record, a death certificate, or correspondence with a tax preparer. The IRS reviews each request individually and decides whether to grant relief.

Having a history of filing on time strengthens your case for reasonable cause. If you have filed late in previous years, the IRS is less likely to grant relief. First-time filers who are late due to genuine hardship have a better chance of penalty removal.

Filing an extension to avoid the failure-to-file penalty

You can file Form 4868 (process for Automatic Extension of Time to File U.S. Individual Income Tax Return) to extend your important date from April 15 to October 15 — an additional six months. Filing this form before the April 15 important date stops the failure-to-file penalty from accruing, even if you file after October 15.

An extension gives you more time to file, but it does not extend the time to pay. If you owe taxes, payment is still due on April 15, even if you file in October. If you do not pay by April 15, the failure-to-pay penalty begins accruing on April 16, regardless of when you file.

Many people file an extension to avoid the failure-to-file penalty while they gather documents or work with a tax professional. This strategy is especially useful if you expect to owe money but need time to prepare the return — you pay the failure-to-pay penalty (0.5 percent per month) but avoid the steeper failure-to-file penalty (5 percent per month).

What happens if you never file

If you never file a return, the IRS can file a Substitute for Return (SFR) on your behalf using information from employers, banks, and other sources. This return typically claims no deductions and results in a much higher tax bill than you would owe if you filed yourself. You then owe the full tax, plus penalties and interest, with no opportunity to claim deductions or credits you were may have access to to.

The IRS can pursue collection actions if you do not file or pay, including wage garnishment, bank levies, and liens on your property. These actions can continue for up to ten years from the date the tax is assessed. Filing late is always better than not filing at all, because filing gives you control over what deductions and credits appear on your return.

Frequently Asked Questions

How much does it cost to file one week late?

If you file one week late and owe $3,000 in taxes, the failure-to-file penalty is $150 (5 percent of $3,000 for one month or part of a month). You also owe interest from April 15 until you pay. If you already filed on time but paid late, you would owe only the failure-to-pay penalty of $15 (0.5 percent of $3,000), making filing on time much cheaper even if you cannot pay when ready.

Do I owe a penalty if I file late but get a refund?

No, there is no failure-to-file penalty if you are due a refund. However, you must file within three years of the original important date to claim the refund. If you file four years late, the IRS keeps the refund. There is also no failure-to-pay penalty because you do not owe taxes.

Can I get the penalty removed if I filed late by mistake?

The IRS may remove the penalty if you can show reasonable cause — for example, if you misunderstood the important date, a tax professional made an error, or you had a serious personal emergency. You must request relief on Form 843 with supporting documents. First-time late filers have a better chance of relief than repeat offenders.

Does filing an extension stop all penalties?

Filing an extension stops the failure-to-file penalty but not the failure-to-pay penalty. If you owe taxes, you must pay by April 15 even if you file in October. Paying late after April 15 triggers the 0.5 percent monthly failure-to-pay penalty, which continues until you pay in full.

What is the difference between a penalty and interest?

Penalties are percentages of unpaid tax charged for specific violations, like filing or paying late. Interest is a charge for the time value of money and accrues on both the tax and the penalties. Interest cannot be waived, but penalties sometimes can be if you show reasonable cause.