IRS Penalty and Interest Calculator
Enter the tax year, what you owed and when you filed and paid. The calculator shows the late-filing penalty, the late-payment penalty and the interest the IRS adds.
IRS Penalty and Interest Estimator
For individual income tax returns (Form 1040). See how late filing and late payment add up.
This is an estimate, not legal or tax advice. It uses the failure-to-file penalty of 5% a month (up to 25%, reduced by the failure-to-pay penalty in the same month, with the IRS minimum when a return is more than 60 days late), the failure-to-pay penalty of 0.5% a month (up to 25%), and IRS quarterly interest rates compounded daily, assuming 7% after December 2026. It assumes the tax and penalties are paid in full on the date you enter. It leaves out interest on the failure-to-pay penalty, which starts only after an IRS bill goes unpaid, the lower 0.25% rate during an approved payment plan for on-time filers, the higher 1% rate after a notice of intent to levy, and the extension safe harbor when at least 90% of the tax was paid by the due date. IRS disaster postponements other than the Los Angeles County option can change due dates.
How IRS Penalties Add Up
Filing late and paying late are two separate penalties. The failure-to-file penalty is 5% of the unpaid tax for each month or part of a month the return is late, up to 25%. The failure-to-pay penalty is 0.5% a month, also up to 25%. In a month when both apply, the filing penalty drops by the payment penalty, so the combined charge is 5% for that month. A return filed more than 60 days late carries a minimum penalty: $525 for returns due in 2026, or the full tax owed if that is less.
The filing penalty is the expensive one. It reaches its 25% limit after five months, while the payment penalty takes more than four years to get there. That is why filing on time, even when you cannot pay, saves money. An extension moves the filing deadline to October but does not move the payment deadline.
How Interest Works
Interest runs on unpaid tax from the original due date and compounds daily. The rate is the federal short-term rate plus 3 points, reset every quarter; it is 7% for the last quarter of 2026. Interest is also charged on the filing penalty from the return's due date. Unlike penalties, interest has no cap and is rarely removed, except when the penalty it was charged on is removed.
Getting Penalties Removed
The IRS removes penalties in two main ways. Administrative relief rewards a clean history: if you filed and paid on time for the three prior years, the penalty can be waived without a reason, and for 2025 and later returns the IRS is applying this automatically from summer 2026 through its Automatic Exemption from Penalty. For earlier years you still request first-time abatement. Reasonable cause relief covers situations outside your control, such as serious illness, a death in the family, a disaster or records you could not obtain.
Talk to a Tax Attorney About Your Numbers
A calculator gives you a starting point. A free, confidential consultation tells you what the IRS is likely to accept in your case.