IFTA Late return
IFTA late filing penalty and interest
File after the due date and your base jurisdiction adds a penalty of $50 or 10% of the tax due, whichever is greater, plus interest on every state you owe for each month or part of a month you are late.
Next return: Q3 2026, due .
Late penalty calculator
The rules, from the IFTA Articles of Agreement
When the return is due
The last day of the month after the quarter: January 31, April 30, July 31 and October 31. When that day is a Saturday, Sunday or legal holiday, the return is due the next business day (R960.100).
Penalty
For a late return, no return, or underpaid tax, the base jurisdiction may assess $50 or 10% of the delinquent tax, whichever is greater (R1220.100). It can add other penalties under its own law (R1220.300); those are not included here.
Interest
Two percentage points above the IRS underpayment rate, set every January 1, charged at 1/12 of the annual rate per month (R1230.100). For 2026 that is 9% a year, 0.75% a month. It is worked out separately for each state you owe, from the due date, and any part of a month counts as a full month (R1230.300).
Worked example
The Q3 2026 return was due Mon, Nov 2, 2026. You owe $1,000 and pay on Tue, Dec 15, 2026: that is 2 months late. Penalty: 10% of $1,000 = $100.00. Interest: $1,000 × 0.75% × 2 = $15.00. Total added: $115.00.
Coming due dates
| Return | Due |
|---|---|
| Q3 2026 | |
| Q4 2026 | |
| Q1 2027 | |
| Q2 2027 |
Weekend dates already moved to Monday. A state holiday can move your base jurisdiction's date too.
Work out the tax for Q4 2026 before the deadline.
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