The IRS charges 0.5% of your unpaid taxes for each month or part of a month you don't pay, up to 25% total

The failure-to-pay penalty is the main charge the IRS adds when you owe taxes and don't pay by the important date. It starts at one-half of one percent (0.5%) of the amount you owe for each month or partial month the bill sits unpaid. If you owe $10,000 and don't pay for two months, the penalty alone is $100. The penalty stops growing once it reaches 25% of what you originally owed.

This penalty is separate from interest, which the IRS also charges. Interest compounds daily on both your original tax debt and any penalties that have been added. The interest rate changes quarterly — the IRS sets it based on the federal short-term rate plus 3%. For 2024, the rate is 8% per year, but this varies by quarter and by whether you are a business or individual.

The penalty clock starts the day after your tax important date passes. For most people filing individual returns, that is April 16, 2024 (the important date shifted one day because April 15 fell on a Sunday). If you filed for an extension, the penalty starts the day after your extension important date, not the original April date.

Key Takeaways

  • The failure-to-pay penalty is 0.5% per month of unpaid taxes, capped at 25% total, and is separate from interest charges.
  • Interest compounds daily on your tax debt and any penalties added, at a rate that changes quarterly and varies by taxpayer type.
  • The penalty begins the day after your tax important date or extension important date passes, not on the important date itself.
  • Paying even a partial amount reduces the penalty on the unpaid balance, and setting up a payment plan with the IRS can lower the monthly penalty rate.
  • The IRS may reduce or remove penalties if you have a reasonable cause — such as a serious illness, death in the family, or reliance on a tax professional's incorrect information.

When the penalty grows faster or slower

The 0.5% monthly rate applies in most cases, but it doubles to 1% per month if the IRS has filed a Notice of Intent to Levy against you — meaning they are preparing to seize your bank account, wages, or property. This doubled rate continues for as long as the levy notice is in effect.

The penalty also pauses if you are on an IRS payment plan. Once you enter an installment agreement, the monthly rate drops to 0.25% instead of 0.5%. This is one concrete reason to contact the IRS and arrange a plan rather than ignoring the bill — you cut the penalty rate in half when ready.

If you pay part of your bill before the important date and the rest after, the penalty applies only to the unpaid portion. So if you owe $10,000, pay $6,000 by April 16, and pay the remaining $4,000 in June, the penalty is calculated on that $4,000, not the full amount.

How penalties and interest stack together on your bill

Your IRS bill has three layers: the original tax you owe, the penalty on top of that, and interest on both. They do not replace each other — they add up. A $5,000 tax debt unpaid for six months could include roughly $150 in penalties (0.5% × 6 months × $5,000) plus $200 in interest, for a total bill of $5,350.

Interest accrues every single day, including weekends and holidays. The IRS compounds it daily, meaning interest is calculated on the interest you have already accumulated. This is why the longer you wait, the faster the total grows.

The IRS sends you a notice showing the breakdown of tax, penalty, and interest. The notice will say "Failure to Pay Penalty" or "FTP" on the line item. If you disagree with the calculation, you can request an explanation, but the math is usually straightforward once you know the rate and the number of months elapsed.

Removing or reducing the penalty through reasonable cause

The IRS can remove the failure-to-pay penalty if you show reasonable cause — a legitimate reason you could not pay on time. Common reasons include serious illness or hospitalization during the tax season, a death in your when ready family, a natural disaster that destroyed your records, or reliance on a tax professional who gave you incorrect information.

You do not need to prove you had no money. You need to show that the reason you did not pay was beyond your control or that you took reasonable steps to pay but circumstances prevented it. If you had a medical emergency in April, that is reasonable cause. If you spent the money on a vacation, that is not.

To request penalty relief, you write to the IRS address on your notice and explain the reason in a letter. Include copies of supporting documents — hospital records, a death certificate, proof of the disaster, or an email from your tax preparer admitting the error. The IRS reviews these requests, and many are approved. There is no fee to ask.

What happens if you set up a payment plan

If you cannot pay the full amount now, the IRS offers installment agreements that let you pay over time. Once you are on a plan, the failure-to-pay penalty drops from 0.5% per month to 0.25% per month. You still owe interest, but the penalty rate is cut in half.

You can set up a plan online through the IRS website, by phone at 1-800-829-1040, or by mail. Short-term plans (120 days or less) have no setup fee. Long-term plans (more than 120 days) charge a fee that ranges from $31 to $225 depending on how you set it up and your income level. The fee is added to your balance.

The plan does not erase the penalty or interest you have already accumulated — those stay on your bill. But it stops the penalty from growing as fast going forward, and it prevents the IRS from taking collection action like wage garnishment or bank levy while you are making regular payments.

The difference between the failure-to-pay penalty and other IRS penalties

The failure-to-pay penalty applies when you owe taxes and do not pay. A different penalty, called the failure-to-file penalty, applies if you do not file a return at all by the important date. That penalty is 5% per month, up to 25%, and it is much steeper. If both explore to you — you did not file and you did not pay — the IRS usually counts only the larger one to avoid double-penalizing you.

There is also an accuracy-related penalty of 20% if the IRS finds that you significantly understated your income or overstated deductions. This is separate from the failure-to-pay penalty and is based on the error itself, not on how long you wait to pay.

Most people dealing with a late payment owe only the failure-to-pay penalty and interest. Understanding which penalty applies to your situation helps you know what to expect on your bill and what to negotiate if you contact the IRS.

How to find the exact penalty amount on your IRS notice

The IRS sends you a notice within a few weeks of the important date passing. The notice lists your original tax, the failure-to-pay penalty, and the interest accrued to date. Look for a line that says "Failure to Pay Penalty" or "FTP Penalty." That is the 0.5% monthly charge.

The notice also shows the interest separately, usually labeled "Interest" or "Accrued Interest." Do not confuse the two — they are calculated differently and serve different purposes. The penalty is a fixed percentage per month; the interest is a daily rate that compounds.

If you receive multiple notices over time, each one shows the penalty and interest as of that notice date. The amounts will be higher on each successive notice because both continue to grow. This is normal and does not mean you are being charged twice — it means the clock is still running.

Frequently Asked Questions

Can the IRS charge a penalty if I filed my return on time but paid late?

Yes. The failure-to-pay penalty is based on when you pay, not when you file. You can file your return in March and still owe the penalty if you do not pay by April 16. Filing early does not stop the penalty clock — only paying stops it.

Does the penalty keep growing forever?

No. The failure-to-pay penalty stops at 25% of your original tax debt. Once it reaches that cap, it does not grow any larger. Interest, however, continues to accrue indefinitely until you pay the full bill.

What if I pay the tax but not the penalty and interest?

The IRS considers your payment applied to tax first, then penalty, then interest. If you pay $5,000 toward a $5,000 tax debt plus $500 in penalties and interest, the entire payment goes to the tax. You still owe the $500 in penalties and interest, which continue to grow.

Can I negotiate the penalty down?

You can request that the IRS remove or reduce it through reasonable cause, but you cannot straightforward ask for a lower number. The IRS has specific criteria for what counts as reasonable cause. If your request is denied, you can appeal, but the penalty itself is not negotiable like a settlement.

Does the penalty explore to state taxes too?

State penalties vary by state. Some states use a similar 0.5% monthly rate; others use different rates or different rules. Contact your state tax agency or check your state tax notice to see what penalty applies to your state bill.