California IFTA Fuel Tax Compliance and Filing Guide

The International Fuel Tax Agreement (IFTA) is a reciprocal agreement between the lower 48 U.S. states and Canadian provinces that simplifies the reporting of fuel use by motor carriers operating in multiple jurisdictions. In California, the California Department of Tax and Fee Administration (CDTFA) manages IFTA accounts, issuing credentials and processing quarterly tax returns. A qualified motor vehicle under IFTA is one that has two axles and a gross vehicle weight (GVW) or registered GVW exceeding 26,000 pounds, has three or more axles regardless of weight, or is used in a combination with a GVW exceeding 26,000 pounds. Carriers based in California must apply for an IFTA license if they operate their qualified motor vehicles in at least one other IFTA jurisdiction. Compliance requires precise tracking of all miles driven in each state and all gallons of fuel purchased. California imposes some of the highest fuel tax rates in the country, currently $0.596 per gallon for diesel as of July 2024. Failure to maintain accurate records can result in audits where the CDTFA may assess taxes based on a standard of 4.0 miles per gallon if documentation is insufficient. DispatchTool assists carriers by automatically calculating jurisdictional mileage and aggregating fuel receipts, which simplifies the preparation of the IFTA-100 and IFTA-101 schedules. Owners can manage these records directly within the platform to ensure every mile is accounted for before the quarterly deadline. Create a DispatchTool account to start automating your mileage tracking for upcoming IFTA filings.

California IFTA Registration and Licensing Fees

To register for an IFTA account in California, carriers must submit form CDTFA-400-MTO through the CDTFA online services portal. Unlike some states that charge an annual flat fee, California currently does not charge a fee for the IFTA license itself, but there is a cost for the decals. Each qualified motor vehicle requires two decals, one for each side of the cab. The cost for a set of two decals is $2.00 per year. Licenses are valid for one calendar year, expiring on December 31. Carriers are granted a grace period until the end of February to display the new year's decals, provided they have submitted their renewal application by the December deadline. If a carrier operates without a valid license or decal, they may be subject to a citation and a fine of $100 to $500, depending on the severity of the violation and prior history.

Quarterly Filing Deadlines and Penalties

California requires quarterly filings even if no taxable fuel was used or no miles were driven during the period. The deadlines are strictly enforced: April 30 for Q1, July 31 for Q2, October 31 for Q3, and January 31 for Q4. If the deadline falls on a weekend or state holiday, the return is due the next business day. Failure to file by the deadline results in a penalty of $50.00 or 10% of the net tax due, whichever is greater. Interest also accrues on any unpaid tax at a rate of 1% per month. According to the CDTFA, electronic filing is mandatory for all IFTA accounts, and payments must be made via ACH transfer, credit card, or check accompanied by a voucher. Maintaining a clean filing history is critical to avoid being selected for a mandatory audit.

California Diesel Fuel Tax Rates and Surcharges

As of July 1, 2024, the California excise tax on diesel fuel is $0.596 per gallon. This rate is subject to annual adjustments every July based on the Consumer Price Index. In addition to the excise tax, California applies a sales tax component to fuel through the IFTA return. When filing the IFTA-101, carriers must distinguish between tax-paid fuel purchased at the pump and fuel pulled from bulk storage. Because California has high tax rates compared to neighboring states like Arizona ($0.26 per gallon) or Nevada ($0.27 per gallon), carriers often see a tax credit on their California return if they buy the majority of their fuel in California but drive significantly in lower-tax jurisdictions. Conversely, carriers fueling in Arizona and driving through California will likely owe a substantial balance.

Record Keeping Requirements for Audits

The CDTFA requires carriers to maintain detailed records for a minimum of four years from the filing date. These records must include Individual Vehicle Mileage Records (IVMRs) that show the date of the trip, origin and destination, route of travel, beginning and ending odometer readings, and total distance traveled in each jurisdiction. Fuel records must include original receipts or invoices showing the date, seller name, fuel type, number of gallons, and the unit number of the vehicle. Summaries are not sufficient for audit purposes; the CDTFA requires source documents. If an audit reveals that records are inadequate, the agency can apply a standard 4.0 MPG to all miles traveled, which usually results in a significant tax liability and additional penalties under California Revenue and Taxation Code Section 9405.

California Fuel Trip Permits

For carriers who do not wish to maintain a permanent IFTA license because they rarely leave California, or for out-of-state carriers who rarely enter California, a Fuel Trip Permit is an alternative. In California, the 4-day Fuel Trip Permit costs $30.00. This permit must be purchased before entering the state and allows the vehicle to operate in California without an IFTA decal for 90 consecutive hours. Carriers are limited to using these permits for occasional trips. If a carrier frequently enters the state, the CDTFA recommends a full IFTA license as the cost-effective solution. These permits only cover fuel taxes; carriers must still comply with California Department of Motor Vehicles (DMV) registration requirements and the California Highway Patrol (CHP) safety regulations.

Exemptions and Special Fuel Types

Not all miles driven are taxable under IFTA in California. Miles driven on private roads or property may be exempt, provided the carrier maintains GPS records or logs that clearly distinguish off-highway travel from public road travel. Additionally, California provides specific tax rates for alternative fuels. For example, Liquefied Natural Gas (LNG) and Compressed Natural Gas (CNG) have different tax conversion factors. As of 2024, the tax rate for LNG is $0.596 per 1.71 gallons (the energy equivalent of one gallon of diesel), while CNG is taxed at $0.0887 per 100 cubic feet. Carriers using alternative fuels must be diligent in selecting the correct fuel code on their quarterly returns to avoid overpayment or underpayment.

Sources

California Department of Tax and Fee Administration (CDTFA) (2024) — https://www.cdtfa.ca.gov/taxes-and-fees/ifta-rates.htm International Fuel Tax Association, Inc. (2025) — https://www.iftach.org California Revenue and Taxation Code (2024) — https://leginfo.legislature.ca.gov/

Frequently asked

What is the penalty for late IFTA filing in California?

The penalty is either $50.00 or 10% of the total tax amount due, whichever is higher. Additionally, interest is charged at 1% per month on any unpaid balance.

How long must I keep IFTA records in California?

Per CDTFA regulations, you must retain all mileage and fuel records, including original receipts and trip logs, for a period of four years.

Do I need an IFTA license if I only drive within California?

No, if you operate exclusively within California, you do not need an IFTA license. IFTA is only required for qualified motor vehicles that cross state or provincial lines.

What is the current California diesel tax rate?

As of July 1, 2024, the California diesel excise tax rate is $0.596 per gallon, which is one of the highest in the United States.

Can I file my California IFTA return by mail?

No, the California Department of Tax and Fee Administration (CDTFA) requires all IFTA licensees to file their quarterly returns electronically through their online portal.