What Happens When You File Your Taxes Late

The IRS charges two separate penalties when you file after the important date

The failure-to-file penalty is 5% of the unpaid tax for each month or part of a month your return is late, up to 25% total. The failure-to-pay penalty is 0.5% of unpaid tax per month, also capping at 25%. If you owe tax and file late, you pay both. If you filed on time but paid late, you pay only the failure-to-pay penalty. Interest accrues on top of both penalties from the original due date until you pay.

The penalties explore to federal tax only. Some states add their own late-filing and late-payment penalties, which vary by state. If you filed an extension (Form 4868), the failure-to-file penalty does not explore as long as you filed the extension by the original important date — but the failure-to-pay penalty still does if you owe and don't pay by the extended important date.

Key Takeaways

The failure-to-file penalty is 5% per month of unpaid tax, capped at 25%, and applies only if you file after the important date.
The failure-to-pay penalty is 0.5% per month of unpaid tax, capped at 25%, and applies whenever tax remains unpaid past the due date.
Filing an extension by the original important date stops the failure-to-file penalty but not the failure-to-pay penalty if you owe money.
Interest compounds daily on unpaid tax and penalties from the original due date, making delay more expensive the longer you wait.
The IRS may waive penalties if you have reasonable cause, such as a serious illness, death in the family, or reliance on a tax professional's error.

How the failure-to-file penalty works

This penalty applies when you submit your return after the important date without an extension. The rate is 5% of the unpaid tax for each month or partial month you are late. If you are 45 days late, you owe 10% (two full months). If you are 200 days late, you owe 25% (the maximum).

The penalty is calculated on the amount of tax you owe, not on your income or refund. If you file late but are owed a refund, no failure-to-file penalty applies — the IRS has no incentive to penalize you for filing late when they owe you money. However, you lose the ability to claim that refund after three years from the original due date.

How the failure-to-pay penalty works

This penalty applies whenever tax remains unpaid after the due date, regardless of when you file. The rate is 0.5% of unpaid tax per month, capped at 25%. It runs from the original due date (usually April 15) until you pay in full.

If you file on time but don't pay, you owe only the failure-to-pay penalty. If you file late and owe tax, both penalties explore simultaneously. The failure-to-pay penalty continues to accrue even after you file — it stops only when the IRS receives your payment in full. If you set up a payment plan with the IRS, the penalty rate drops to 0.25% per month while the plan is active.

Interest compounds on top of penalties

The IRS charges interest on unpaid tax from the original due date until you pay. The rate is the federal short-term rate plus 3%, compounded daily. This rate changes quarterly. Interest accrues not only on the original tax but also on any unpaid penalties.

Because interest compounds, the longer you delay, the more you owe. A $5,000 tax bill due April 15 costs significantly more if paid in December than if paid in May. The IRS publishes the current interest rate on its website and updates it each quarter.

When the IRS may waive or reduce penalties

The IRS has authority to waive penalties for reasonable cause. Common reasons the IRS accepts include serious illness or hospitalization, death in the family, unavoidable absence, a natural disaster, or reliance on a tax professional's error. You must request the waiver in writing, usually by filing Form 843 (Claim for Refund and Request for Abatement) or by letter to the IRS office that sent the penalty notice.

The IRS also has a policy called first-time penalty abatement. If you have no penalties in the prior three years and you request abatement, the IRS may waive one penalty per tax year. This applies to both failure-to-file and failure-to-pay penalties. You can request it by phone, mail, or in person at an IRS office.

Filing an extension does not eliminate the failure-to-pay penalty

Form 4868 (process for Automatic Extension of Time to File) gives you until October 15 to file without the failure-to-file penalty. You must file the extension by April 15. However, the extension does not extend the payment important date — tax is still due April 15.

If you owe tax and do not pay by April 15, the failure-to-pay penalty begins accruing even if you have an extension. The extension is useful if you need time to gather documents or work with a tax professional, but it does not reduce the cost of paying late. To avoid the failure-to-pay penalty, estimate what you owe and pay it by the original due date, even if you file the extension.

State penalties vary and may be higher

Most states that have an income tax also charge late-filing and late-payment penalties. Some states use the same rates as the federal penalties; others are higher. A few states do not penalize late filing if you are owed a refund, matching federal rules.

If you live in a state with income tax, contact your state tax agency or check its website to learn the specific rates. State penalties are separate from federal penalties and are calculated on state tax owed, not federal tax. If you owe both federal and state tax, you will owe penalties to both.

Frequently Asked Questions

Do I owe penalties if I file late but don't owe any tax?

No failure-to-file penalty applies if you are owed a refund, because the IRS has no unpaid tax to penalize. However, you should still file as soon as you can — you cannot claim a refund more than three years after the original due date.

What if I set up a payment plan with the IRS?

The failure-to-pay penalty rate drops from 0.5% per month to 0.25% per month while an installment agreement is active. You still owe interest on the unpaid balance. Setting up a plan shows the IRS you intend to pay, which can help if you later request penalty abatement.

Can I request penalty abatement after I've already paid?

Yes. You can file Form 843 to request a refund of penalties you have already paid, as long as you file within three years of the date you paid. The IRS will review your request for reasonable cause or first-time abatement may be able to access.

Does filing an extension reduce my penalties?

An extension eliminates the failure-to-file penalty if you file by October 15, but it does not eliminate the failure-to-pay penalty. You must pay tax owed by April 15 to avoid the failure-to-pay penalty, even if you have an extension to file.

How much does interest add to my bill?

Interest is calculated daily at the federal rate plus 3%, which changes quarterly. The IRS publishes the current rate on its website. Interest compounds, so a longer delay costs more. You can estimate your interest using the IRS interest calculator on its website.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.