For individuals, IRS interest is 7% a year in the fourth quarter of 2026, and it compounds daily. It runs on top of penalties. The failure to pay penalty adds 0.5% a month, up to 25%. Filing late adds 5% a month, up to 25%.
Interest starts on the due date and keeps running until the balance is paid in full. It also grows on the penalties.
If you filed but did not pay, the failure to pay penalty is 0.5% of the unpaid tax each month, up to 25%. On a payment plan, if you filed on time, it drops to 0.25% a month.
If you did not file, the failure to file penalty is 5% a month, up to 25%. That is ten times bigger, so file on time even if you can't pay.
For returns due after Dec 31, 2025 that are over 60 days late, the smallest failure to file penalty is $525 or 100% of the tax, whichever is less.
Key facts
- Interest: 7% a year for individuals, Q4 2026
- Failure to pay: 0.5% a month, up to 25%
- Failure to file: 5% a month, up to 25%
- On a plan, filed on time: 0.25% a month
Next steps
General information, not tax or legal advice. Updated October 28, 2026. Sources are linked.