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IFTA Articles of Agreement • State Jurisdiction Reporting

IFTA Fuel Tax Quarterly Filing Blueprint

Understand how the International Fuel Tax Agreement works, why buying cheap diesel in low-tax states can create a surprise tax bill at quarter-end, and how to defend against state DOT audit penalties.

6 min read•Audited for 2026 State Fuel Tax Schedules

01Who is Subject to IFTA Licensing?

The International Fuel Tax Agreement (IFTA) is an agreement between the 48 contiguous U.S. states and 10 Canadian provinces to simplify the reporting of fuel taxes by commercial carriers. A vehicle is considered a "qualified motor vehicle" subject to IFTA if it is used, designed, or maintained for transportation of persons or property and:

QUALIFICATION RULE
Combination Weight Exceeds 26,000 lbs

Any combination vehicle where the gross combination weight rating (GCWR) or gross combination registered weight is 26,001 pounds or more.

NON-CDL EXEMPTION
Under 26,000 lbs = 100% IFTA Exempt

If your truck and trailer combination is legally registered and plated at 26,000 lbs or under (e.g. 10k truck + 15.9k trailer), you are completely exempt from IFTA licensing and quarterly filings.

02The 4 Strict Quarterly Filing Deadlines

IFTA returns must be submitted to your base jurisdiction (your home state) every calendar quarter, even if you ran zero miles:

QUARTER 1Jan 1 – Mar 31Due April 30
QUARTER 2Apr 1 – Jun 30Due July 31
QUARTER 3Jul 1 – Sep 30Due October 31
QUARTER 4Oct 1 – Dec 31Due January 31

03The 3-Step IFTA Mathematical Formula

IFTA does not care where you bought your fuel—it cares where you burned it. The formula works in three steps:

Step 1: Calculate Fleet Overall MPGTotal Miles Driven (All States) ÷ Total Gallons Purchased = Fleet Average MPG
Step 2: Determine Gallons Burned in Each StateMiles Driven in State ÷ Fleet Average MPG = Taxable Gallons for State
Step 3: Calculate Net Tax Owed or Refund Due(Taxable Gallons × State Tax Rate) − Tax Already Paid at the Pump = Net Balance

04The Draconian "4.0 MPG Penalty" Audit Trap

Save Every Diesel Receipt for 4 Years

If your base state audits your IFTA report and you are missing fuel receipts or odometer distance records, the auditor has the statutory legal power to throw out your recorded MPG and assess all miles at a statutory 4.0 MPG penalty rate. This can instantly result in a retroactive fuel tax assessment of $4,000 to $12,000 plus a 10% penalty and 1% monthly interest. Always use a commercial fuel card (like OTR Solutions / EFS) that automatically logs date, location, gallons, and pump taxes paid.