Idaho IFTA Fuel Tax Compliance and Reporting

The Idaho State Tax Commission (IDT) manages the International Fuel Tax Agreement (IFTA) for motor carriers based in the state. Idaho-based carriers operating qualified motor vehicles in two or more member jurisdictions must register for an IFTA license to report and pay fuel use taxes through a single agency. A qualified vehicle is defined by the IDT as one having two axles and a gross vehicle weight exceeding 26,000 pounds, having three or more axles regardless of weight, or used in combination with a total weight exceeding 26,000 pounds. Carriers failing to maintain compliance face penalties of $50 or 10% of the tax due, whichever is greater, plus interest. DispatchTool assists Idaho owner-operators by automating the collection of GPS-based mileage data and fuel purchase records required for quarterly filings. By tracking miles driven specifically within Idaho versus neighboring jurisdictions like Oregon (which has distinct weight-mile tax rules) or Washington, the platform reduces manual entry errors and ensures that the total distance reported matches the individual jurisdiction breakdowns. Create a DispatchTool account to generate the trip reports needed for your next Idaho IFTA quarterly return.

Registration and Idaho Credentials

To register for IFTA in Idaho, a carrier must have an established place of business in the state, maintain operational control from an Idaho location, and have records available for audit in the state. The Idaho State Tax Commission does not charge a fee for the annual IFTA license or the two required decals per vehicle. However, carriers must renew their credentials annually by December 31. A grace period allows carriers to display the previous year's decals until February 28, provided they have a valid renewal application on file by the end of the year. If a carrier does not wish to register for IFTA, they must purchase hazardous materials or temporary fuel permits for $40 per 96-hour period when entering other jurisdictions.

Quarterly Filing Deadlines and Penalties

Idaho IFTA returns are due on the last day of the month following the close of the quarter. For 2025, the deadlines are April 30 (Q1), July 31 (Q2), October 31 (Q3), and January 31 (Q4). If the due date falls on a weekend or state holiday, the return is considered timely if postmarked by the next business day. The IDT imposes a late penalty of $50 or 10% of the net tax due, whichever is greater. Interest is calculated at the underpayment rate established by the IFTA Articles of Agreement, which is typically the adjusted prime rate plus 1%. Even if no miles were driven during a quarter, a 'No Operations' return must still be filed to avoid license cancellation.

Idaho Fuel Tax Rates and Exemptions

As of early 2025, the Idaho state fuel tax rate for both gasoline and special fuels (diesel) is $0.32 per gallon. Idaho does not offer a refund for fuel used in idling or for auxiliary power units (APU) if the fuel is drawn from the main propulsion tank. However, fuel used in equipment with a separate tank, such as a refrigeration unit (reefer), is not subject to the IFTA tax. Carriers must strictly separate these fuel purchases in their records. Under Idaho Statute 63-2401, 'special fuel' includes diesel, biodiesel, and natural gas used to operate motor vehicles on public highways. It is critical to note that while Idaho is an IFTA member, neighboring Oregon is not; miles driven in Oregon are not reported on the IFTA return but are subject to Oregon's weight-mile tax.

Record Keeping Requirements

Under the Idaho State Tax Commission guidelines, carriers must retain records for four years from the filing date. These records must include Individual Vehicle Mileage Records (IVMR) containing the date of the trip, trip origin and destination, routes of travel, odometer readings (beginning and ending), and total distance. Fuel records must include original receipts or invoices showing the date of purchase, name and address of the seller, number of gallons purchased, and the vehicle identification number (VIN) of the truck receiving the fuel. Digital records are acceptable if they meet the standards set by the IFTA Procedures Manual. Failure to produce these records during an audit can result in the assessment of taxes based on a standard 4.0 miles per gallon (MPG) consumption rate.

Online Filing via TAP

Idaho requires most carriers to file their IFTA returns electronically through the Taxpayer Access Point (TAP). This portal allows carriers to upload data, calculate taxes owed or credits due, and make payments via ACH or credit card. When filing, the system automatically calculates the net tax due by subtracting the tax-paid gallons from the tax-consumed gallons across all jurisdictions. If a carrier has a net credit, they can choose to apply it to the next quarter or request a refund check. Refunds of less than $10 are not issued but are carried forward as a credit. The TAP system also allows carriers to order additional decals throughout the year if they expand their fleet.

Sources

Idaho State Tax Commission - IFTA Guide (2025) — https://tax.idaho.gov/business-taxes/fuel-tax/ifta/ International Fuel Tax Association, Inc. (2025) — https://www.iftach.org/ Idaho Statutes Title 63, Chapter 24 (2024) — https://legislature.idaho.gov/statutesrules/idstat/title63/t63ch24/

Frequently asked

What is the penalty for not filing an Idaho IFTA return?

The Idaho State Tax Commission charges a minimum penalty of $50 or 10% of the tax liability, whichever is larger, for late or missing returns.

How long must I keep my fuel receipts in Idaho?

Idaho law requires you to maintain all IFTA-related records, including fuel receipts and mileage logs, for a minimum of 4 years.

Does Idaho charge for IFTA decals?

No, the Idaho State Tax Commission provides the annual IFTA license and vehicle decals at no cost to the carrier.

Are reefer fuel purchases included in the IFTA total?

No, fuel used in a separate tank for a refrigeration unit is exempt from IFTA reporting in Idaho, provided it is not used to propel the vehicle.