IRS Tax Penalty & Interest Calculator (2025 Estimates)

IRS Penalty Snapshot (2025)

Failure-to-File: 5% per month (maximum 25%)

Failure-to-Pay: 0.5% per month (maximum 25%)

Installment Agreement Rate: 0.25% per month

Interest: Federal short-term rate + 3%, compounded daily (IRS quarterly rate)

These rates are based on current IRS rules and may change if federal interest rates are adjusted quarterly.

Quick Summary of IRS Late Filing and Late Payment Penalties

If you owe the IRS and file your tax return late or pay your taxes late, IRS penalties and interest begin accruing immediately. The Failure-to-File penalty is typically 5% per month (up to 25%). The Failure-to-Pay penalty is usually 0.5% per month (up to 25%). IRS interest compounds daily at the federal short-term rate plus 3%. Filing an extension removes the Failure-to-File penalty, but not the Failure-to-Pay penalty. Use the calculator above to estimate your total amount owed, including penalties and interest.

How IRS Tax Penalties Work

When taxes are not filed or paid by the original deadline (typically April 15), the IRS may assess:

1. Failure-to-File penalty
2. Failure-to-Pay penalty
3. Daily compounded interest

If you’re unsure about the deadline or whether you still have time to act, review your extension deadline options or explore tax extension help before penalties increase further.

Separate penalties may apply for underpayment of estimated taxes throughout the year, which are calculated differently from late filing and late payment penalties.

Failure-to-File Penalty (Late Return)

Rate: 5% of unpaid tax per month
Maximum: 25% of unpaid tax
Authority: IRC §6651(a)(1)

The Failure-to-File penalty applies when you do not submit your tax return by the original due date. If you need additional time to submit your return, you may be able to avoid this penalty by filing a tax extension using Form 4868 before the deadline.

Important details:

• Charged for each month (or part of a month), the return is late.
• If both Failure-to-File and Failure-to-Pay apply, the 5% rate is reduced by the 0.5% Failure-to-Pay rate (net 4.5% per month).
• If your return is more than 60 days late, a minimum penalty may apply.

Failure-to-Pay Penalty (Late Payment)

Rate: 0.5% of unpaid tax per month
Maximum: 25% of unpaid tax
Reduced Rate: 0.25% per month with an approved installment agreement
Authority: IRC §6651(a)(2)

The Failure-to-Pay penalty applies when taxes are not paid by the due date, even if the return was filed on time. If you cannot pay in full, reviewing your payment plans and penalty options may help reduce how quickly penalties accrue.

Key points:

• Accrues monthly (or partial month).
• Continues until tax is paid in full.
• Reduced once an installment agreement is approved.

IRS Interest on Unpaid Taxes

Rate: Federal short-term rate + 3%
Compounding: Daily
Authority: IRC §6601

Interest is charged on:

• Unpaid tax
• Penalties once assessed

Interest rates are updated quarterly by the IRS. Even if you request an extension or set up a payment plan, interest generally continues accruing until the balance is paid in full.

If you’re considering your options, understanding how extensions, payment plans, and penalties work together can help you minimize total cost.

Penalty Rule Summary

IRS Failure-to-File Rule

Rate: 5% per month
Maximum: 25%
Trigger: Return filed after original tax deadline
Authority: Internal Revenue Code §6651(a)(1)

IRS Failure-to-Pay Rule

Rate: 0.5% per month
Reduced Rate: 0.25% with an installment agreement
Maximum: 25%
Authority: Internal Revenue Code §6651(a)(2)

IRS Interest Rule

Rate: Federal short-term rate + 3%
Compounding: Daily
Authority: Internal Revenue Code §6601

IRS Penalty Rates by Scenario

When Do IRS Penalties Start?

Penalties begin accruing from the original tax due date, not the extension deadline.

Example:

• Tax year 2025 return due: April 15, 2026
• Extension deadline: October 15, 2026

If you file an extension but do not pay by April 15:

• Failure-to-File: Does not apply
• Failure-to-Pay: Begins April 15
• Interest: Begins April 15

Does Filing an Extension Reduce Penalties?

Filing an extension can help in some situations, but it does not eliminate all IRS penalties.

Filing an extension:

• Removes the Failure-to-File penalty
• Does NOT remove the Failure-to-Pay penalty
• Does NOT stop interest

If you need additional time to submit your return, you can extend your tax deadline before the original due date. However, it’s important to understand that an extension gives you more time to file paperwork, not more time to pay.

Many taxpayers wonder whether filing an extension is bad or if it increases audit risk. In most cases, filing properly and on time (even with an extension) is better than filing late without one.

If you expect to owe taxes, paying as much as possible by the original deadline reduces penalties and interest. Avoiding common extension mistakes, such as failing to estimate your payment correctly, can also help limit additional charges.

Some taxpayers assume there is an automatic penalty for filing an extension, but the penalty typically applies only if taxes remain unpaid after the original deadline.

How IRS Interest Is Calculated

IRS interest compounds daily using this formula:

Daily Interest = (Unpaid Balance × Annual Rate) ÷ 365

Example:

• $10,000 unpaid
• 8% annual interest rate

Daily interest = ($10,000 × 0.08) ÷ 365
= $2.19 per day

Over time, interest compounds on both tax and penalties.

Real Example: Late Filing and Late Payment

When filing late (or facing late filing for the first time), it’s easy to underestimate how quickly the IRS adds penalties plus daily interest. Here’s a simple example to show how late filing and late payment can increase what you owe.

Scenario:

• Tax owed: $10,000
• Filed 4 months late
• Paid 6 months after due date
• No installment agreement

Failure-to-File:

4 months × 5% = 20%
20% × $10,000 = $2,000

Failure-to-Pay:

6 months × 0.5% = 3%
3% × $10,000 = $300

Interest:

Accrued daily on tax + penalties

Total amount owed will exceed $12,300 after penalties and daily compounded interest.

Use the calculator above to estimate your specific scenario.

Can IRS Penalties Be Reduced?

You may qualify for:

• First-time penalty abatement
• Reasonable cause relief
• Installment agreement
• Offer in Compromise
• Currently Not Collectible status

Penalty relief depends on filing history, payment history, and circumstances.

If penalties exceed your ability to pay, consider speaking with a tax professional about formal relief options.

Related Tax Calculators

If you’re estimating what you owe, these additional tools may help:

• Federal income tax calculator – Estimate your federal income tax liability before penalties and interest.
• Explore all available tax calculators to plan, compare, and estimate different tax scenarios.

Important Disclaimer

This calculator provides estimates based on general IRS rules. Actual penalties and interest may vary based on individual circumstances, IRS rate changes, and payment timing. For official guidance, refer to IRS publications or consult a licensed tax professional.

FileTax is not affiliated with the Internal Revenue Service. This tool is an independent estimator based on published IRS rules.