What the IRS charges when you pay taxes late

The late payment penalty is a fee the IRS adds to your tax bill when you do not pay the full amount by the deadline. The penalty is calculated as a percentage of the unpaid tax, and it grows each month you do not pay. The IRS does not waive this penalty often, and it stacks on top of interest charges that also accrue on the unpaid balance.

The standard late payment penalty is 0.5% of your unpaid tax for each month or part of a month that the payment is late. If you owe $5,000 and you are one month late, the penalty is $25. If you remain unpaid for six months, the penalty reaches $150. The penalty can reach a maximum of 25% of your unpaid tax, at which point it stops growing.

This penalty applies whether you filed your tax return on time or not. If you filed late and paid late, you face both a failure-to-file penalty and a failure-to-pay penalty. The two penalties do not add together in a simple way — the IRS reduces the failure-to-file penalty by the failure-to-pay penalty to avoid double-charging you, but you still owe both.

Key Takeaways

  • The late payment penalty is 0.5% of your unpaid tax per month, capped at 25% total.
  • Interest on the unpaid tax is separate from the penalty and continues to accrue as long as the debt exists.
  • The penalty applies even if you filed your return on time but paid late.
  • Setting up a payment plan with the IRS does not stop the penalty, but it does stop additional failure-to-pay penalties from growing after you enter the plan.

How the penalty is calculated and when it starts

The IRS begins charging the late payment penalty the day after your payment deadline. For most individual tax returns, that deadline is April 15. If you file an extension, the deadline moves to October 15, but the penalty clock starts the moment the original April 15 deadline passes if you have not paid by then.

The penalty is calculated on the amount of tax you still owe, not on your total tax liability. If you paid $3,000 of a $5,000 bill on time, the penalty applies only to the remaining $2,000. The IRS recalculates the penalty each month based on what you still owe, so making a partial payment reduces the base amount the penalty is charged against going forward.

The penalty accrues for each month or part of a month. If you are late by even one day into a new month, you owe a full month's penalty for that month. This means paying on the 31st of a month costs the same penalty as paying on the 1st of the next month.

Late payment penalty versus interest and other charges

The late payment penalty and interest are two separate charges. Interest is the cost of borrowing money from the IRS; it accrues daily and is calculated as a percentage of the unpaid tax. 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 typically between 8% and 9% per year, but this varies.

Interest continues to accrue even after the late payment penalty reaches its 25% cap. This means your total debt can grow significantly if you remain unpaid for years. A $5,000 unpaid tax bill can easily become $7,000 or more once penalties and interest are added.

If you filed your return late, you may also owe a failure-to-file penalty, which is 5% of your unpaid tax per month (capped at 25%). The IRS applies a credit to avoid charging you both the failure-to-file and failure-to-pay penalties at full strength, but you still owe a combined penalty that is higher than either one alone.

When the IRS stops charging the late payment penalty

The late payment penalty stops growing once it reaches 25% of your unpaid tax. At that point, no additional penalty accrues, even if you remain unpaid for years. However, interest continues to accrue indefinitely until the debt is paid.

If you enter into a payment plan with the IRS — either an installment agreement or an offer in compromise — the failure-to-pay penalty rate drops to 0.25% per month instead of 0.5%. This reduced rate applies only to months after you have entered the plan. Any penalty that accrued before the plan was established remains on your bill.

The penalty does not disappear if you file an amended return or if circumstances change. The only way to remove it is to pay the full amount owed, to reach a settlement with the IRS through an offer in compromise, or in rare cases, to request penalty relief if you can show reasonable cause for the late payment.

Requesting penalty relief from the IRS

The IRS has the authority to remove or reduce the late payment penalty in certain situations, but this is not automatic. You must request it, and you must provide a reason that the IRS considers reasonable cause. Common reasons include serious illness, death in the family, fire or natural disaster, or reliance on incorrect advice from a tax professional.

Simply not having money to pay is not considered reasonable cause. Neither is not understanding the deadline or forgetting to pay. The IRS is more likely to grant relief if you have a history of paying on time and this is your first late payment in several years.

To request relief, you can call the IRS at 1-800-829-1040, write to the address on your notice, or work through a tax professional or enrolled agent. You will need to explain your situation in writing and provide supporting documents — medical records for illness, death certificates for a death in the family, or proof of the disaster. The IRS will review your request and notify you of the decision by mail.

How late payment penalties affect your total tax debt

The late payment penalty is added to your bill each month, which means your total debt grows faster than it would from interest alone. On a $10,000 unpaid tax bill, the penalty alone adds $50 in the first month, $100 by the second month, and so on. Over two years, the penalty could add $2,500 to your bill before it caps out.

This is why paying even a partial amount quickly can save money. If you can pay $5,000 of a $10,000 bill within the first month, you reduce the base amount the penalty is charged against for all future months. The remaining $5,000 will still accrue penalties and interest, but the total penalty will be lower than if you had paid nothing.

If you cannot pay the full amount, contact the IRS to discuss a payment plan. The reduced penalty rate under a payment plan (0.25% instead of 0.5%) can save hundreds of dollars over time, and it stops the penalty from growing indefinitely.

Frequently Asked Questions

Can I avoid the late payment penalty if I file an extension?

Filing an extension moves your filing deadline to October 15, but it does not extend your payment deadline. If you do not pay by April 15, the late payment penalty begins accruing on April 16, even if you filed an extension. The extension only gives you more time to file the return itself, not to pay the tax.

Does the penalty stop if I set up a payment plan?

The penalty does not stop, but the rate drops from 0.5% per month to 0.25% per month once you enter a payment plan. Any penalty that accrued before you set up the plan stays on your bill. The reduced rate applies only to months after the plan begins.

What happens if I pay the penalty but not the tax?

You cannot pay only the penalty. The penalty is part of your total tax debt, and the IRS will not accept a payment that covers the penalty but leaves the underlying tax unpaid. Any payment you make is applied to the tax first, then to interest and penalties.

How long does the IRS have to collect the late payment penalty?

The IRS generally has 10 years from the date the tax was assessed to collect the debt, including penalties and interest. After 10 years, the debt expires and the IRS can no longer pursue collection, though there are exceptions that can extend this period.

Will the penalty go away if I ignore the bill?

No. The penalty continues to accrue (up to the 25% cap) whether you pay or not. Ignoring the bill also triggers additional collection actions — the IRS can place a lien on your property, garnish your wages, or seize your bank account. Contacting the IRS to set up a payment plan or discuss your options is always better than ignoring the debt.