Interstate User Diesel Fuel Tax

Interstate User Diesel Fuel Tax (Interstate User)

Under the Interstate User Diesel Fuel Tax program, every person using diesel fuel to operate a qualified motor vehicle within and outside California must pay a tax for every gallon of diesel fuel used in California.

Generally, you are required to hold an Interstate User Diesel Fuel Tax License or obtain a California Fuel Trip Permit (CFTP) if:

  • You operate at least one qualified motor vehicle powered by diesel fuel,
  • You travel only in California and Mexico, or
  • You travel in California and your business is based outside California in a jurisdiction that is not a member of the International Fuel Tax Agreement (IFTA).
    • Currently, the nonmember jurisdictions are Mexico; Alaska, Hawaii, and the District of Columbia (DC); and Canada's Nunavut, Yukon Territory, and Northwest Territories.

If you operate a qualified motor vehicle in California and any other U.S. state, you should register for an International Fuel Tax Agreement License. Please see the International Fuel Tax Agreement (IFTA) page for more information.

If you operate a diesel-powered vehicle whose travel is solely in California, you do not need an IFTA or Interstate User Diesel Fuel Tax License.

Qualified Motor Vehicle

A vehicle used or designed to transport people or property is considered a qualified motor vehicle if it:

  • Has three or more axles; or
  • Has two axles and a gross vehicle or registered gross vehicle weight of more than 26,000 pounds or 11,797 kilograms; or
  • Is used in a combination that has a combined or registered gross vehicle weight of more than 26,000 pounds or 11,797 kilograms.

A recreational vehicle, such as a motor home or a pickup with a camper, is not considered a qualified motor vehicle when an individual uses it exclusively for personal pleasure. Vehicles used in connection with a business operation are not considered recreational.

Diesel Fuel

Diesel fuel includes any liquid that is commonly or commercially known or sold as a fuel that is suitable for use in a diesel-powered highway vehicle.

Diesel fuel does not include kerosene, gasoline, liquefied petroleum gas, natural gas in liquid or gaseous form, or alcohol. See the Use Fuel Tax Guide for list of fuels subject to the use fuel tax.

Traveling Interstate Without an Interstate User Diesel Fuel Tax License

If you need to enter California and do not have your Interstate User Diesel Fuel Tax License, you must purchase a California Fuel Trip Permit (CFTP) before entering California.

Visit our California Fuel Trip Permit page for information on how to obtain a permit. You must purchase a CFTP and complete it prior to entering California.