The IRS charges you a penalty when you pay your tax bill after the due date

The failure-to-pay penalty is a charge the IRS adds to your tax bill if you do not pay by April 15 (or the extended important date if you filed for an extension). The penalty is 0.5% of the unpaid tax for each month or part of a month that the payment is late. This means the longer you wait to pay, the more the penalty grows — it can reach up to 25% of your unpaid tax if you never pay.

The penalty applies whether you owe a small amount or a large one. It also applies even if you filed your return on time — the penalty is only about payment, not filing. If you filed late and paid late, you may owe both a failure-to-file penalty and a failure-to-pay penalty.

The IRS also charges interest on top of the penalty. Interest is separate from the penalty and accrues daily on any unpaid tax. The interest rate changes quarterly and is set by the IRS. Both the penalty and interest are added to what you already owe.

Key Takeaways

  • The failure-to-pay penalty is 0.5% of your unpaid tax per month or part of a month, up to a maximum of 25%.
  • Interest accrues daily on your unpaid tax and is charged in addition to the penalty.
  • The penalty starts the day after your payment due date, even if you have a valid reason for paying late.
  • You can reduce or remove the penalty if you have reasonable cause, such as a serious illness or death in your family.
  • Setting up a payment plan with the IRS does not stop the penalty from accruing, but it shows the IRS you intend to pay.

When the penalty starts and how it grows

The penalty begins on the day after your tax payment is due. If you owe taxes on your 2023 return, the due date is April 15, 2024. If you did not pay by that date, the penalty starts on April 16, 2024. The IRS counts any part of a month as a full month, so even if you pay on May 1, you owe the penalty for the entire month of April.

The penalty compounds monthly. If you owe $5,000 and pay two months late, the penalty is 1% of $5,000, or $50. If you pay six months late, the penalty is 3% of $5,000, or $150. The maximum penalty is 25%, which means the IRS stops adding the penalty once it reaches that amount — but by then you owe an extra $1,250 on a $5,000 debt.

Interest continues to accrue even after the penalty reaches its maximum. This is why the total cost of paying late can be much higher than the penalty alone.

How interest is different from the penalty

Interest and the penalty are two separate charges. The penalty is a fixed percentage (0.5% per month) that stops growing at 25%. The interest is a daily charge that never stops growing as long as you owe money.

The IRS sets the interest rate each quarter. For most recent years, the rate has been between 8% and 9% per year, but it changes. The interest is calculated daily on your unpaid tax, the penalty, and any previous interest. This means interest compounds — you pay interest on the interest you already owe.

On a $5,000 unpaid tax, interest alone could add $400 to $450 per year if the rate is 8% to 9%. Over several years, interest can cost more than the penalty.

Exceptions and situations where the penalty may not explore

The IRS does not charge the failure-to-pay penalty if you paid at least 90% of your 2024 tax by April 15, 2024. This is called the safe harbor rule. If you paid 90% or more through withholding, estimated tax payments, or a payment before the due date, you owe no penalty on the remaining 10%, even if you pay it late.

You also do not owe the penalty if you are on an IRS payment plan (called an installment agreement). However, the penalty still accrues while you are on the plan — it just does not explore to the first month of the plan. Once you set up the plan, the penalty rate drops to 0.25% per month instead of 0.5% per month.

If you filed for an automatic extension, the penalty does not explore if you paid your estimated tax by the original due date (April 15). The extension gives you until October 15 to file your return, but not to pay your tax.

Requesting penalty relief for reasonable cause

You can ask the IRS to remove or reduce the penalty if you have a valid reason for paying late. The IRS calls this reasonable cause. Common reasons include serious illness or injury, death of a family member, a natural disaster, or reliance on a tax professional who made a mistake.

To request relief, you must write to the IRS and explain why you could not pay on time. You will need to include documentation — a doctor's note for illness, a death certificate for a death in the family, or a letter from your tax preparer if they made an error. Send your request to the IRS address on your notice, along with a copy of the notice itself.

The IRS reviews reasonable cause requests on a case-by-case basis. There is no may provide your request will be approved, but the IRS does grant relief in many cases. If you have a history of paying on time, your request is more likely to be approved.

Payment plans and how they affect the penalty

If you cannot pay your full tax bill by the due date, you can set up a payment plan with the IRS. A payment plan does not remove the penalty or interest, but it does lower the penalty rate to 0.25% per month (half the normal rate) once the plan is in place.

There are two types of payment plans: a short-term plan (you pay within 180 days) and a long-term installment agreement (you pay over several months or years). Short-term plans have no setup fee. Long-term plans charge a setup fee that ranges from $31 to $225 depending on how you set up the plan and your income level.

Even on a payment plan, interest continues to accrue daily. The plan straightforward spreads your payments over time and reduces the penalty rate. If you stop making payments on the plan, the IRS can cancel it and the penalty rate goes back to 0.5% per month.

What happens if you ignore the penalty

If you do not pay your tax bill and do not set up a payment plan, the IRS will send you notices. The first notice is a bill showing what you owe, including the penalty and interest. If you do not respond, the IRS sends additional notices and may eventually file a tax lien against your property or garnish your wages.

A tax lien is a legal claim on your assets. It does not take your property, but it makes it hard to sell your home or borrow money. A wage garnishment means the IRS orders your employer to send part of your paycheck directly to the IRS until the debt is paid.

The longer you wait, the more the penalty and interest grow. A $3,000 unpaid tax can become $4,000 or more within a year or two when you add penalty and interest. Contacting the IRS early — even if you cannot pay the full amount — is always better than waiting.

Frequently Asked Questions

Can I get the penalty removed if I paid late but filed on time?

The penalty is based on payment, not filing. You can still owe the failure-to-pay penalty even if you filed your return by April 15. However, you may be able to request reasonable cause relief if you have a valid reason for the late payment, such as illness or a family emergency.

Does the penalty stop growing after a certain point?

Yes. The failure-to-pay penalty stops at 25% of your unpaid tax. However, interest continues to accrue daily and never stops. So while the penalty has a cap, your total debt keeps growing because of interest.

What is the difference between a payment plan and paying the full amount late?

A payment plan lowers the penalty rate from 0.5% per month to 0.25% per month and shows the IRS you intend to pay. Without a plan, the full 0.5% penalty applies each month. Interest accrues in both cases, but a plan can save you money on penalties over time.

If I set up a payment plan, do I still owe interest?

Yes. A payment plan reduces the penalty rate but does not stop interest from accruing. Interest is calculated daily on your unpaid tax, the penalty, and any previous interest. The plan straightforward spreads your payments over time.

How do I request reasonable cause relief?

Write a letter to the IRS explaining why you could not pay on time and include supporting documents (medical records, death certificate, etc.). Send it to the address on your IRS notice along with a copy of the notice. The IRS reviews each request individually, and approval is not may provide.