IRS Penalty & Interest Calculator

Estimate late-filing and late-payment penalties plus interest.

Unpaid tax ($)

Original due date

Date return filed (blank if not filed)

Date paid (blank = today)

Interest rate (%/yr)

Set quarterly by the IRS (7% Q1 2026, 6% Q2 2026, 7% Q3 2026)

How IRS penalties are calculated

Failure to file: 5% of unpaid tax for each month or part of a month the return is late, up to 25%.
Failure to pay: 0.5% per month, up to 25%. It drops to 0.25% a month while an approved payment plan is in place (if you filed on time).
Both in the same month: the failure-to-file penalty is reduced by the failure-to-pay amount, so the combined rate is 5%.
Interest: the federal short-term rate + 3%, compounded daily, set each quarter.

Frequently asked questions

Can IRS penalties be removed?

Often. First-time penalty abatement is available if you have a clean record for the past three years, and reasonable-cause relief applies to things like serious illness or disasters.

Is interest charged on penalties?

Yes. Interest generally accrues on penalties as well as unpaid tax, so paying sooner reduces both.

Sources

Written by the editorial team and checked against the official sources above. See our editorial policy.

Last reviewed 2026-11-12. Estimates only — confirm with the IRS or a tax professional.