Tax (IRS) · free tool

IRS Penalty + Interest Estimator

IRS Penalty + Interest Estimator (confirm/fix of existing tool) It’s free, runs in your browser, and stores nothing you enter.

Unpaid tax balance

Months late (part of a month counts as a month)

Was the RETURN filed late (not just paid late)?Is an installment agreement in effect?

Estimated penalties + interest

On top of $0 owed — about $0 total today. Interest actually compounds daily and resets quarterly; this is a close monthly approximation.

Failure-to-file penalty$0

Failure-to-pay penalty$0

Interest (~6%/yr)$0

Estimated balance today$0

Illustrative estimate using current IRS penalty rules and the Q2-2026 interest rate. Interest compounds daily and the rate changes quarterly; the IRS may assess differently. Not legal or tax advice. This is an illustrative estimate for general informational purposes only. It is not legal, tax, or financial advice, it does not create an attorney–client relationship, and it is not a quote, promise, prediction, or guarantee of any benefit, amount, eligibility, deadline, or outcome. Figures are based on published government sources as of the date shown and change over time; results may not reflect current law or the facts of your situation. Do not rely on this tool — consult a licensed attorney before taking or refraining from any action.

Key figures behind this estimate

Published government figures used in the calculation, with their effective date and source.

Failure-to-File penalty

As of 2026 · IRS — Failure to File Penalty (5%/mo, max 25%; reduced by FTP in any month both apply)

Failure-to-Pay penalty

As of 2026 · IRS — Failure to Pay Penalty (0.5%/mo, 0.25% while an installment agreement is in effect, max 25%)

0.5%

Minimum FTF penalty (returns required to be filed in 2026)

As of 2026 · IRS — Failure to File Penalty minimum for returns over 60 days late

$525

Underpayment interest rate — Q2 2026 (individuals)

As of 2026 · IRS Rev. Rul. 2025-22 — interest rates, quarter beginning April 1, 2026 (federal short-term rate + 3%)

Frequently asked questions

What does the IRS Penalty + Interest Estimator estimate?

IRS Penalty + Interest Estimator (confirm/fix of existing tool) It runs entirely in your browser and stores nothing you enter.

Are the figures current?

Yes. The estimate uses published government figures, each dated on this page (as of 2026) with its source.

Is this calculator legal advice?

No. It is an informational estimate from published data and does not create an attorney–client relationship. Confirm specifics with a licensed attorney.

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Illustrative estimate using current IRS penalty rules and the Q2-2026 interest rate. Interest compounds daily and the rate changes quarterly; the IRS may assess differently. Not legal or tax advice.