Montana IFTA Fuel Tax Compliance Guide

The International Fuel Tax Agreement (IFTA) in Montana is administered by the Montana Department of Transportation (MDT). Motor carriers based in Montana that operate qualified motor vehicles in two or more member jurisdictions must obtain an IFTA license to report and pay fuel taxes. A qualified motor vehicle is defined by the MDT as a vehicle used for business with two axles and a gross vehicle weight exceeding 26,000 pounds, three or more axles regardless of weight, or a combined weight exceeding 26,000 pounds. Proper record-keeping is critical, as Montana requires carriers to maintain distance and fuel records for four years from the filing date. Filing occurs quarterly through the MDT e-Part online system. Carriers must report all miles traveled in Montana and other jurisdictions, alongside total fuel purchased. Calculating these figures manually is prone to error, especially when tracking individual state mileages across the Interstate 15 or Interstate 90 corridors. DispatchTool simplifies this process by generating detailed mileage reports per jurisdiction based on actual truck-safe routes driven, which can be directly imported into IFTA worksheets. Carriers can manage their trip data and document storage in one central location to ensure audit readiness. Create a DispatchTool account to streamline your quarterly Montana fuel tax calculations.

Licensing and Decal Requirements

To qualify for a Montana IFTA license, the carrier must have an established place of business in the state and maintain their operational records in Montana or make them available for audit. The MDT does not charge an annual fee for the IFTA license itself, but two decals are required for each qualified vehicle at a cost of $0.50 per set as of 2024. These decals must be displayed on both sides of the exterior cab. Licenses are valid for one calendar year, expiring on December 31, and renewals should be submitted via the e-Part system by November 30 to ensure delivery of new decals before the January 1 deadline.

Quarterly Filing Deadlines and Late Penalties

Montana strictly enforces quarterly filing deadlines. Returns are due by the last day of the month following the close of the quarter: April 30, July 31, October 31, and January 31. If the due date falls on a weekend or legal holiday, the next business day is the deadline. Failure to file a return, filing late, or underpaying results in a penalty of $50 or 10% of the net tax due, whichever is greater. Additionally, interest is charged at a rate of 1% per month, calculated as 1/12th of the annual rate on the unpaid tax amount due to each jurisdiction.

Record Keeping and Distance Tracking

The MDT requires carriers to maintain an Individual Vehicle Distance Record (IVDR) for every unit. These records must include the date of the trip, origin and destination, route of travel using specific highway numbers like MT-200 or US-93, and odometer readings at jurisdictional borders. Total distance must be separated by jurisdiction. Fuel records must include original invoices or credit card receipts showing the date, seller name, gallons purchased, and the equipment number. Montana mandates that these records be kept for four years to satisfy audit requirements under the IFTA Articles of Agreement.

Montana Fuel Tax Rates and Exemptions

As of late 2024, the Montana state tax rate for undyed diesel is $0.2975 per gallon, and the gasoline tax rate is $0.33 per gallon. Montana does not currently provide exemptions for idling time or Power Take-Off (PTO) usage within the IFTA return for fuel consumed on the highway. All miles traveled within the state are considered taxable miles unless the vehicle is operated strictly on private property with documented proof. It is important to note that dyed diesel is strictly prohibited for highway use and carries heavy civil penalties if detected during MDT roadside inspections.

The e-Part System and Online Filing

Montana utilizes the Electronic Permit and Registration (e-Part) system for all IFTA transactions. This portal allows carriers to file quarterly tax returns, pay liabilities via ACH or credit card, and order additional decals. When filing, the system automatically calculates the tax or credit due based on the data entered for each jurisdiction. If a carrier has a net credit, they can choose to apply it to future quarters or request a refund. Refunds exceeding $25 are typically processed within 30 to 60 days of the filing date, provided there are no outstanding liabilities in other tax categories.

Audit Selection and Procedures

Under IFTA guidelines, the Montana Department of Transportation is required to audit 3% of its IFTA accounts every year. Audits verify the accuracy of reported miles and fuel purchases. If a carrier fails to provide adequate records, the auditor may impose an assessment based on the best information available, which often results in a fuel economy of 4.0 miles per gallon being applied to all miles traveled. This frequently leads to significant tax assessments and additional penalties. Maintaining digital logs and organized fuel receipts is the primary defense against unfavorable audit findings.

Sources

Montana Department of Transportation (2024) — https://www.mdt.mt.gov/business/mcss/ifta.aspx IFTA, Inc. Official Site (2025) — https://www.iftach.org Montana Code Annotated 15-70-121 (2023) — https://leg.mt.gov/bills/mca/title_0150/chapter_0700/part_0010/section_0210/0150-0700-0010-0210.html

Frequently asked

What is the cost for Montana IFTA decals?

Montana charges a fee of $0.50 per set of two decals. The license itself has no base fee, but carriers must be in good standing with all state taxes to receive them.

Can I file my Montana IFTA return by mail?

The Montana Department of Transportation strongly encourages electronic filing through the e-Part system. While paper forms may be available upon request for specific hardship cases, the majority of carriers are required to use the online portal for efficiency and accuracy.

What happens if I don't travel outside of Montana for a quarter?

You must still file a 'Zero Miles' return if you have an active IFTA license but did not operate outside the state during the quarter. Failure to file a zero-mile return will result in a $50 late filing penalty.

How long should I keep my fuel receipts in Montana?

According to MDT and IFTA regulations, you must retain all fuel and distance records for a period of 4 years from the date the tax return was filed or required to be filed.

Are there temporary fuel permits for Montana?

Yes, if you do not have an IFTA license, you must purchase a Montana temporary fuel permit before entering the state. The fee is $30 for a 72-hour permit or a specific trip, which allows for legal operation without an IFTA decal.