The IRS charges two separate penalties when you file after the deadline

If you file your tax return after April 15 (or the extended deadline if you requested one), 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 usually steeper, so filing even a few days late costs more than paying late.

The failure-to-file penalty is 5% of the unpaid taxes for each month or part of a month that your return is late, up to a maximum of 25%. The failure-to-pay penalty is 0.5% of unpaid taxes per month, also capped at 25%. If you file on time but pay late, you only owe the failure-to-pay penalty. If you file late and owe money, you owe both.

Interest also accrues on unpaid taxes from the original due date, compounded daily. The interest rate changes quarterly and is set by the IRS based on the federal short-term rate plus 3%. As of 2024, the rate is 8% annually, but this varies by quarter.

Key Takeaways

  • Filing late triggers a 5% monthly penalty on unpaid taxes (up to 25%), separate from the 0.5% monthly penalty for paying late.
  • Interest on unpaid taxes runs from the original April 15 deadline and compounds daily, regardless of when you file.
  • If you file on time but pay late, you avoid the filing penalty and only owe the smaller payment penalty plus interest.
  • The IRS may waive penalties if you have reasonable cause, such as a death in the family, serious illness, or a mistake by a tax professional you hired.
  • Filing a return showing a refund owed has no penalty, even if you file years late, because you owe nothing.

How the failure-to-file penalty is calculated

The failure-to-file penalty starts at 5% of your unpaid tax liability for each month or partial month your return is late. If you file one day late and owe $1,000, you owe a $50 penalty. If you file two months late, the penalty is $100. The penalty maxes out at 25% of unpaid taxes, which means filing more than five months late does not increase the penalty further.

The clock starts the day after the deadline. If the deadline is April 15 and you file April 16, you are one day late. If you file May 1, you are 16 days late, which counts as one full month for penalty purposes. The IRS rounds up any partial month.

This penalty does not apply if you file a return showing you are owed a refund. Even if you file a refund return 10 years late, there is no penalty. The IRS only penalizes you for filing late when you owe money.

How the failure-to-pay penalty works

The failure-to-pay penalty is 0.5% of unpaid taxes per month or partial month, capped at 25%. This penalty applies whether you file on time or late. If you owe $1,000 and pay 30 days late, you owe a $5 penalty. After 50 months of non-payment, the penalty reaches its maximum of $250.

The failure-to-pay penalty is smaller than the failure-to-file penalty, which is why filing on time even without payment is better than filing late. If you file on April 15 but cannot pay until June 15, you owe only the 0.5% monthly penalty. If you file on June 15 and cannot pay until August 15, you owe both the 5% monthly filing penalty and the 0.5% monthly payment penalty.

If you set up a payment plan with the IRS, the failure-to-pay penalty is reduced to 0.25% per month while the plan is active. This is one reason to contact the IRS before the deadline if you know you cannot pay in full.

Interest on unpaid taxes

Interest accrues on any unpaid tax from the original due date, not from the date you file or the date the IRS assesses the tax. The interest rate is set quarterly by the IRS and is currently 8% annually as of 2024, though it changes. Interest compounds daily, meaning you owe interest on the interest.

Interest is separate from penalties. If you owe $1,000 in taxes and file two months late, you owe $100 in failure-to-file penalty, $10 in failure-to-pay penalty, and roughly $13 in interest (depending on the exact dates and the current rate). These amounts stack.

Interest continues to accrue until you pay in full. There is no cap on interest, unlike penalties. If you owe $1,000 and do not pay for five years, interest alone could exceed $400.

When the IRS may waive or reduce penalties

The IRS can waive the failure-to-file and failure-to-pay penalties if you have reasonable cause. This is not a formal list but includes circumstances beyond your control: a death in the immediate family, serious illness or hospitalization, a fire or natural disaster that destroyed your records, or reliance on incorrect advice from a tax professional you paid to prepare your return.

You must request the waiver in writing, usually by mail or through your IRS account. Include a brief explanation of the reason for the late filing and any supporting documents (a death certificate, hospital records, proof of the disaster, or a letter from the tax professional). The IRS reviews the request and decides whether to grant it.

Reasonable cause does not include simply forgetting the deadline, being too busy, or not understanding the rules. The IRS is more likely to grant a waiver if this is your first penalty in several years or if you have a history of filing on time.

Penalties for filing more than 60 days late

If you file more than 60 days after the deadline, the minimum failure-to-file penalty is $435 (as of 2024) or 100% of the unpaid tax, whichever is smaller. This is a floor, not a cap. If you owe $200 in taxes and file 61 days late, you owe at least $435 in penalty alone, even though the tax is only $200.

This rule applies whether you file 61 days late or two years late. The penalty does not increase further after 60 days, but it is substantially higher than the 5% monthly penalty that applies before the 60-day mark. This is a strong incentive to file before the 60-day threshold.

What to do if you have not filed in multiple years

If you have not filed returns for several years, penalties and interest compound. A return filed three years late owes three years of failure-to-file penalties plus three years of interest. However, the IRS has a process for catching up called amended return filing or simply filing the unfiled returns in order, starting with the oldest year.

Contact the IRS at 1-800-829-1040 or visit irs.gov to request copies of your tax transcripts and to ask about payment plans. The IRS often works with people who file multiple years of back returns, especially if you are owed refunds in some years (which can offset what you owe in others). Filing the returns stops the accrual of new penalties for those years, though penalties and interest for the years already late remain.

Frequently Asked Questions

Do I owe a penalty if I file on time but pay late?

No failure-to-file penalty, but yes to the failure-to-pay penalty. You owe 0.5% of unpaid taxes per month, capped at 25%, plus interest from the original due date. This is much cheaper than filing late, so always file by the deadline even if you cannot pay.

What if I filed late but the IRS owes me a refund?

There is no penalty for filing a refund return late, even years late. The IRS only penalizes late filing when you owe money. However, refunds are subject to a statute of limitations — you generally cannot claim a refund more than three years after the original due date.

Can I get the penalty removed if I have a good reason?

Yes, if you have reasonable cause. Death in the family, serious illness, a natural disaster, or reliance on a paid tax professional's incorrect advice are common reasons the IRS accepts. Request a waiver in writing with supporting documents. First-time penalties and a history of on-time filing improve your chances.

Does an extension deadline change when penalties start?

Yes. If you file Form 4868 before April 15, you get an automatic six-month extension to October 15. Penalties for late filing do not start until after October 15. However, interest on unpaid taxes still runs from April 15, so an extension does not reduce interest owed.

How much will I owe if I file one year late?

If you owe $1,000 in taxes and file 12 months late, you owe a maximum of $250 in failure-to-file penalty (25% cap), $60 in failure-to-pay penalty (12 months × 0.5%), and roughly $80 in interest at current rates. The exact interest depends on the quarter and compounding, but penalties and interest together typically add 30% to 40% to the original tax owed.