IRS Penalty and Interest Calculator: Late Filing and Late Payment
Enter what you owed, when it was due, when you filed and when you paid, and see the failure-to-file penalty, the failure-to-pay penalty and the interest added on top.
The IRS charges three things on tax paid late: a failure-to-file penalty of 5% of the unpaid tax for each month or part month the return is late, up to 25%; a failure-to-pay penalty of 0.5% a month, also up to 25%; and interest compounded daily at the quarterly underpayment rate, 7% in all four quarters of 2025. On $5,000 due April 15, 2025, filed August 1 and paid October 15, that comes to about $1,228.58.
This page estimates penalties and interest for general education. It is not tax advice or legal advice, and it is not a substitute for your tax notice. It assumes one full payment on the date you enter and no extension, payment plan, levy notice or penalty relief, and it leaves out interest on penalties, state penalties and estimated-tax penalties. Your actual balance comes from your tax notice. Check with a qualified tax professional before making decisions.
Estimated penalties and interest
$1,228.58
| Failure to file (4 months late) | $900.00 |
| Failure to pay (6 months) | $150.00 |
| Interest on the tax (183 days) | $178.58 |
Interest rates used: 2025 Q2 7%, 2025 Q3 7%, 2025 Q4 7%.
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About the IRS Penalty and Interest Calculator
Two separate penalties apply to late federal tax, and the filing one is far larger. Filing late costs 5% of the unpaid tax for every month or part of a month after the due date, but in any month when both penalties apply, the filing penalty drops by the 0.5% paying-late charge, so five months of both comes to 22.5% for filing late on top of the paying-late charge. After five months the filing penalty stops growing while the paying penalty keeps running to its own 25% cap. A return more than 60 days late also has a minimum penalty: for returns due in 2025 it is $510 or the whole unpaid tax, whichever is less, and $525 for returns due in 2026. Interest is separate. It runs from the due date on the unpaid balance, compounded daily, at the federal short-term rate plus 3 points, which is reset each quarter. This page uses the published rates from 2017 through the fourth quarter of 2026. It charges interest on the tax only; interest is also added on penalties, so the real figure is somewhat higher.
Frequently asked questions
Is it better to file on time even if I cannot pay?+
Yes. Filing on time removes the failure-to-file penalty, which is ten times the monthly rate of the failure-to-pay penalty. On $5,000 unpaid, filing four months late with the tax also paid late adds $900, and filing late but paying on time adds $1,000, because the paying charge reduces the filing penalty only in months both apply. Paying late on its own adds $25 a month.
Why does one day late count as a full month?+
Both penalty rules say the charge applies for each month or part of a month. A payment one day after the due date is charged a full 0.5%, and the next month's charge starts the day after the same date the following month.
What does this estimate leave out?+
Partial payments, extensions to file, approved payment plans (which cut the paying penalty to 0.25% a month after an on-time return), the 1% rate after a notice of intent to levy, penalty relief such as first-time abatement, and interest on the penalties themselves. Your tax notice is the final figure.
Can the penalties be removed?+
Sometimes. Relief exists for reasonable cause and a first-time abatement for people with a clean recent record, and penalties removed this way also lose the interest charged on them. Interest on the tax itself is generally not removed.
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