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 got an extension), the IRS charges a failure-to-file penalty. This is a percentage of the taxes you owe, calculated monthly. You also owe failure-to-pay penalties on any balance due, which is a separate charge that starts accruing the day the return was due. Both penalties compound with interest, which the IRS charges daily on unpaid taxes.

The exact dollar amount depends on how much tax you owe and how many months late you file. The IRS does not charge a penalty if you filed on time but paid late — only if the return itself arrives after the important date. If you are owed a refund, there is no penalty, though you lose interest the government would have paid you.

Key Takeaways

  • The failure-to-file penalty is 5 percent of unpaid taxes for each month or part of a month you are 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, and runs separately from the filing penalty.
  • Interest accrues daily on all unpaid taxes at a rate set quarterly by the IRS, currently in the range of 8 to 9 percent annually depending on the quarter.
  • If you filed on time but paid late, you owe only interest and the failure-to-pay penalty, not the failure-to-file penalty.
  • Filing even one day after the important date triggers the penalty, but the IRS may waive it if you have reasonable cause and a clean filing history.

How the failure-to-file penalty is calculated

The failure-to-file penalty is 5 percent of your unpaid tax balance for each month or partial month that your return is late. If you file two months late, the penalty is 10 percent. If you file six months late, it is 25 percent — and that is the maximum, even if you file years later.

The penalty applies only to taxes you actually owe. If your withholding and estimated payments already covered your full tax bill, or if you are owed a refund, there is no failure-to-file penalty. The IRS calculates it based on the tax shown on your return minus any payments you made by April 15.

Example: You owe $3,000 in taxes. You file on June 15 (two months late). The failure-to-file penalty is 5 percent × 2 months = 10 percent of $3,000, which is $300. You owe the $3,000 in taxes plus the $300 penalty, plus interest on both amounts.

How the failure-to-pay penalty works separately

The failure-to-pay penalty is 0.5 percent of unpaid taxes per month, capping at 25 percent. It runs at the same time as the failure-to-file penalty and is calculated on the same unpaid balance, but it is a separate charge. This means you can owe both penalties simultaneously.

The failure-to-pay penalty starts on the original due date of your return, not the date you filed. If you filed on time but did not pay by April 15, the failure-to-pay penalty clock started on April 15, even if you did not file until later. This is why filing on time but paying late is less expensive than filing late — you avoid the failure-to-file penalty entirely.

Using the same example: You owe $3,000 and file two months late. The failure-to-pay penalty is 0.5 percent × 2 months = 1 percent of $3,000, which is $30. Combined with the failure-to-file penalty of $300, you now owe $330 in penalties on top of the $3,000 tax and the interest.

Interest compounds daily on the full amount owed

Beyond the penalties, the IRS charges interest on any unpaid taxes. The interest rate is set quarterly and varies — it is currently between 8 and 9 percent per year depending on which quarter you are in, though this rate changes. Interest accrues daily on the unpaid tax balance, the penalties, and any previously accrued interest.

Interest is not capped. It continues to accrue until you pay in full. The longer you wait, the more interest you owe. The IRS publishes the current interest rate on its website and updates it each quarter, so the exact rate depends on when your return was due.

Using the example again: On the $3,000 tax plus $330 in penalties ($3,330 total), interest accrues daily. At 8 percent annually, that is roughly $0.73 per day. After one year of non-payment, you would owe approximately $3,330 plus $266 in interest, plus the penalties are still accruing.

When the IRS may waive the penalties

The IRS can waive the failure-to-file and failure-to-pay penalties if you have reasonable cause. This means you had a valid reason you could not file or pay on time — not just that you forgot or did not think about it. Common reasons the IRS accepts include serious illness, a death in the family, a natural disaster, or reliance on a tax professional who made an error.

You must have a clean filing history to may have access to. If you have a pattern of late filings or payments, the IRS is unlikely to grant a waiver. You request a waiver by filing your return and including a written explanation of why you were late, or by calling the IRS at the number on your notice after they assess the penalty.

The IRS does not automatically waive penalties. You have to ask, and you have to provide documentation of your reason. Even with reasonable cause, the IRS may reduce the penalty rather than eliminate it entirely. Interest, however, is never waived — it is a charge for using the government's money, not a penalty for behavior.

What happens if you owe a refund instead

If you filed late but are owed a refund, there is no failure-to-file penalty and no failure-to-pay penalty. The IRS straightforward processes your return and sends you the refund. However, you do lose interest. The government pays interest on refunds that are delayed, but only from the original April 15 important date to the date they issue the refund. If you file late, the interest clock starts from your filing date, not from April 15, so you receive less interest than you would have if you filed on time.

The interest rate on refunds is the same as the interest rate on unpaid taxes, set quarterly by the IRS. It is typically lower than what you would owe if you were the one paying late, but it is still money you lose by filing late.

Filing an extension does not eliminate the late-filing penalty

If you file Form 4868 (process for Automatic Extension of Time to File U.S. Individual Income Tax Return) by April 15, the IRS automatically grants you until October 15 to file. However, the extension applies only to filing, not to payment. If you owe taxes and do not pay by April 15, you owe the failure-to-pay penalty starting April 15, even though you have until October 15 to file.

If you then file after October 15, you also owe the failure-to-file penalty. The extension buys you time to file without penalty, but not time to pay without penalty. To avoid penalties entirely, you must both file and pay by the extended important date — October 15 in this case.

Frequently Asked Questions

Do I owe a penalty if I file late but do not owe any taxes?

No. The failure-to-file penalty applies only to unpaid taxes. If your withholding and payments already covered your full tax bill, or if you are owed a refund, there is no penalty. You may lose some interest on a refund, but there is no penalty charge.

What if I filed on time but paid late?

You owe the failure-to-pay penalty (0.5 percent per month) and interest, but not the failure-to-file penalty (5 percent per month). This is significantly cheaper than filing late. The failure-to-pay penalty starts on April 15, regardless of when you actually pay.

Can the IRS remove penalties after I pay?

The IRS can remove or reduce penalties if you show reasonable cause — serious illness, death in the family, natural disaster, or error by a tax professional. You must request this in writing or by phone after receiving a penalty notice. Interest cannot be removed, only penalties.

How long does the IRS have to collect penalties and interest?

The IRS generally has 10 years from the date they assess the tax to collect it. However, this period can be extended if you do not file a return or if you commit tax fraud. Penalties and interest accrue during this entire period.

What if I cannot pay the full amount right now?

You can set up a payment plan with the IRS through their website or by calling them. Interest and penalties continue to accrue while you pay, but a payment plan stops the IRS from taking collection action like wage garnishment or bank levies. The sooner you file and set up a plan, the less interest you will owe overall.