Late Filing and Late Payment Penalty Calculator

This calculator estimates the two common federal income-tax penalties that appear when a taxpayer files late, pays late, or does both. The failure-to-file penalty is generally 5% of unpaid tax for each month or part of a month the return is late, capped at 25%. The failure-to-pay penalty is generally 0.5% of unpaid tax for each month or part of a month the balance remains unpaid, also capped at 25%.

When both penalties apply in the same month, the IRS reduces the failure-to-file penalty by the failure-to-pay penalty for that month. Under the standard 0.5% failure-to-pay rate, that makes the overlap month 4.5% for late filing plus 0.5% for late payment.

If the return is more than 60 days late, a minimum failure-to-file penalty can apply. For returns due in 2026, IRS guidance lists the minimum as $525 or 100% of unpaid tax, whichever is less. The calculator applies that minimum when it is larger than the regular percentage-based filing penalty.

Failure to file is usually more expensive than failure to pay

The late filing penalty is usually much larger than the late payment penalty. That is why filing as soon as possible often matters even if you cannot pay the entire balance immediately. Filing can stop the failure-to-file penalty from growing while the failure-to-pay penalty continues at the lower monthly rate.

A valid extension can help with the filing side. Use the IRS Tax Extension Deadline Calculator to confirm the filing deadline and payment deadline. The extension may delay the filing penalty, but it usually does not delay the payment penalty.

How the monthly penalty count works

IRS penalties generally count each month or part of a month after the deadline. That means filing one day late can count as one month for penalty purposes. This calculator follows that planning convention: it counts partial months after the relevant deadline instead of prorating by exact days.

The failure-to-file clock uses the original filing deadline unless a valid filing extension applies. The failure-to-pay clock uses the original payment due date because an extension to file does not normally extend the time to pay.

Penalty rates and caps

Interest is separate from penalties

The calculator intentionally excludes interest. IRS interest on unpaid balances compounds daily and can change quarterly. Interest can also apply to penalties after assessment or notice rules. Use the penalty estimate as a planning layer, then compare it with IRS notices or current IRS interest-rate guidance.

If your late payment happened because estimated payments were missed during the year, use the Estimated Tax Payment Due Date Calculator to plan the next deadline before the balance grows further.

Penalty relief may be available

IRS penalty relief can apply in some cases. Common paths include first-time penalty abatement, reasonable cause, statutory exceptions, and administrative relief. Relief is fact-specific, so a calculator cannot decide whether you qualify. It can, however, help you estimate the amount at stake before reviewing IRS relief rules or speaking with a tax professional.

Keep the research moving with IRS Tax Extension Deadline Calculator, Tax Refund Calculator 2026, Estimated Tax Payment Due Date Calculator, and FICA Tax Calculator.