Fare basis code

A fare basis code (often just referred to as a fare basis) is an alpha or alpha-numeric code used by airlines to identify a fare type and allow airline staff and travel agents to find the rules applicable to that fare. Although airlines now set their own fare basis codes, there are some patterns that have evolved over the years and may still be in use.

Fare codes start with a letter called a booking code (indicating travel class among other things) which almost always matches the letter code that the reservation is booked in. Other letters or numbers may follow. Typically a fare basis will be 3 to 7 characters long. but can be up to 8.

The first character of the fare basis code is always a letter, and will almost always match the booking code. Booking codes are the identifiers used by the airline's revenue management department to control how many seats can be sold at a particular fare level. For example, a plane may have 25 economy seats still available and the airline may show it in a reservation system as Y7 K5 M4 T6 E3 which indicates how many of each fare type can be reserved. Some codes cannot be sold by agents, and those seats may be reserved for international connections, loyalty programs, or airline staff relocation.

Booking codes used to be standardized, and were defined by IATA. However, airlines have deviated from the IATA standard and current booking codes are airline specific. The same code may have quite different meanings for tickets issued by different airlines. Nevertheless, certain booking codes have fairly standardized meanings across nearly all airlines, and have maintained these meanings for many years:

Letters and numbers in other sections of the fare basis code may provide the following information:

There is an endless list of other codes on modern fares. These are not standardized in any way, and may often be for short-term use. Examples are...

It is common for a multi-sector air ticket to have more than one fare basis, particularly if it is for carriage on more than one airline. The issuing airline may often have an interline agreement to allow other airlines on the ticket. One disadvantage of this system is that if any change is made, the most restrictive fare rule, and/or the highest change fee, may apply to the entire ticket, not just the portion being changed.

In a Global Distribution System, the fare basis will typically display as part of a fare display, and will not normally be shown in an availability display. Some modern booking systems allow availability searches using parameters such as time of day and lowest fare, and may negate the need for an agent to firstly study the fare basis rules.

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