Tax Guide for Motor Fuels Online Filing

Motor fuels online filing is offered to provide a more convenient method of filing motor fuels (aircraft jet fuel, motor vehicle fuel, and diesel fuel [other than International Fuel Tax Agreement (IFTA) and interstate user diesel fuel tax]) tax forms (returns and reports). It allows you to file tax forms in the EDI or flat (FLT) file formats by secure Internet connection. Our online services system validates the data submitted, prepares the data to be processed, and acknowledges filings. The type of online filing method used will depend on the type of motor fuels tax form you are filing. See Online Filing Methods below for more information.


The online filing of tax information has the following advantages:

  • No paper motor fuels tax forms need to be filed and no signature documents need to be completed and mailed.
  • Follows Federation of Tax Administrators (FTA) uniform online filing standards (EDI X12 v.4030).
  • Similar mapping requirements to IRS ExSTARS online filing requirements (EDI X12 v.4030).
  • No postage expenses.
  • Faster processing.
  • Online security ensures confidentiality of data.
  • Less physical file storage space required since data may be stored online.


Motor fuels online filing uses the Internet to receive and transmit motor fuels tax forms. It incorporates the following technological attributes to ensure data security:

  • Username
  • Password, and
  • Data Encryption.

You must also use security procedures that are reasonably sufficient to ensure that all transmissions of motor fuels tax forms are authorized. You must take the necessary precautions to safeguard your technological attributes and notify the CDTFA when you have knowledge that your technological attributes have been compromised.

Getting Started

You must connect to the CDTFA website to submit your files and use a browser that supports 128 bit SSL. Usernames and passwords are required. A Secure Socket Layer (SSL) encrypted session will be established between you and the CDTFA when you log in. Your system must be configured to accept cookies. The CDTFA Online Services system requires a cookie as an element in maintaining the secure internet connection.

Log In Procedures

You must go to our Online Services login page and enter your Username and password.

Online Filing Methods

There are three basic filing methods to file motor fuels tax forms online:

Electronic Data Interchange (EDI)

A computer-to-computer exchange of routine business data in a standard format. For pure EDI, computer-to-computer means an original or sending application program to a processing or receiving application program. EDI consists only of business data, not verbiage or free-form messages. EDI requires a file upload of transactional data that builds the return. There are two versions of EDI available:

  • IRS EDI X12 v 4030 — The terminal operator report and common carrier report may both be filed with the CDTFA in the IRS EDI format.
  • CDTFA EDI X12 v 4030 — Multiple tax form may be submitted in a single transmission.

Flat file (FLT)

A FLT file is a file containing records that have no structured interrelationship. The term is frequently used to describe a textual document from which all word processing or other structure characters or markup have been removed. The CDTFA-required form of FLT file is one in which table data is gathered in lines of ASCII text with the value from each table cell separated by a tab and each row represented with a new line. This type of FLT file is also known as a tab-delimited flat file. FLT requires a file upload of transactional data that builds the return.

Online Tax Form Filing

  • You complete tax forms directly online.
  • Allows a diesel fuel exempt bus operator to submit a CDTFA-501-DB2A schedule by adding a file in our online services system.
  • Available to diesel fuel exempt bus operator and diesel fuel government entity filers August 12, 2019, for reporting periods July 2019 and after.