Fares & pricing Travel technology glossary

Fare rulesAirline fare rules (ATPCO rule categories)

Also called fare conditionsATPCO categoriesrule categoriesCat 1–35

Definition

Fare rules are the conditions an airline attaches to a fare, covering who can buy it, when it can be sold and flown, how it combines with other fares, and what changes or refunds cost. In filed fares they are coded in numbered ATPCO categories so systems can apply them automatically.

What Fare rules means

A price on its own is not a fare. Each fare carries rules that decide whether a booking qualifies and what happens later if the traveller changes plans. The fare is identified by its fare basis code, and the rules sit behind that code.

For fares distributed through ATPCO, rules are organised into numbered categories. Travelport's published list (current as of May 2021) includes Category 1 Eligibility, 2 Day/Time, 3 Seasonality, 4 Flight Application, 5 Advance Reservations/Ticketing, 6 Minimum Stay, 7 Maximum Stay, 8 Stopovers, 9 Transfers, 10 Combinations, 11 Blackout Dates, 12 Surcharges, 13 Accompanied Travel, 14 Travel Restrictions, 15 Sales Restrictions, 16 Penalties, 17 HIP/Mileage Exceptions, 18 Ticket Endorsements, 19 to 22 discounts, 23 Miscellaneous Provisions, 25 Fare by Rule, 26 Groups, 27 Tours, 28 Visit Another Country, 29 Deposits, 31 Voluntary Changes, 33 Voluntary Refunds and 35 Negotiated Fare Restrictions.

Some categories are machine-readable instructions, others are mainly text. ATPCO notes that Category 16 Penalties is display text, while Categories 31 and 33 carry the structured data that lets systems calculate change and refund charges automatically. Category 15 and Category 35 are central to private fares and net fares, because they restrict who may sell or ticket a fare.

How Fare rules works

Rules are filed with the fare and checked by the pricing engine each time the fare is quoted, ticketed or changed.

  1. FilingThe airline files fares and attaches rule data by category, either for a specific fare or as general rules for a market.
  2. MatchingWhen an itinerary is priced, the engine finds candidate fares and tests each applicable category against the booking details.
  3. ValidationFares that fail a category, for example an advance purchase or minimum stay, are discarded and the next eligible fare is tried.
  4. Display to the agentAgents can request the rules as short or full text, or as structured data for selected categories, before booking.
  5. After ticketingFor a change or refund, the system applies the voluntary change and refund categories that were valid on the original ticketing date.

Fare rules in practice

Illustrative. A traveller holds an economy return with these rule highlights:

  • Cat 5: ticket within 72 hours of booking and at least 14 days before departure.
  • Cat 6: stay must include a Saturday night.
  • Cat 16 text: changes permitted for a fee, no refund after departure.
  • Cat 31: change fee plus any fare difference, applied automatically at reissue.

If the traveller moves the return date, the agent's system reads Cat 31 to calculate the charge instead of the agent working it out by hand. If the booking is not ticketed in time, Cat 5 means the fare can no longer be used and the booking may be cancelled at the ticketing time limit.

Who uses it

Travel agenciesAgents read fare rules before quoting so customers know about penalties, minimum stays and ticketing deadlines, reducing the risk of debit memos.
AirlinesPricing teams use rule categories to fence cheaper fares from higher ones and control which channels and passengers can use them.
Corporate travel managersThey compare change and refund rules across fares when setting travel policy for flexible or restricted tickets.
Software developersBooking engines request structured rule categories through GDS or airline APIs to show conditions and automate reissues and refunds.

Advantages and limitations

Advantages

  • A shared category structure lets one filing be applied consistently across GDSs and other pricing systems.
  • Structured change and refund data allows automated reissues instead of manual calculation.
  • Clear rules let airlines offer cheaper restricted fares alongside flexible ones.

Limitations

  • Rule text can be long and technical, which makes it hard to explain to customers.
  • Not every category is fully automated, so some conditions still need manual reading.
  • Errors in rule filing or interpretation can lead to agency debit memos for incorrect tickets.

Frequently asked questions about Fare rules

How many ATPCO fare rule categories are there?

The automated rule categories are numbered from 1 to 35, but not every number is in use; for example, 24, 30, 32 and 34 do not appear in Travelport's list. Some systems also show an additional application and other conditions section, numbered 50, for general text.

What is the difference between Category 16 and Category 31?

Category 16 Penalties is mainly descriptive text about change and cancellation charges. Category 31 Voluntary Changes holds structured data that pricing systems use to calculate a change fee and fare difference automatically when a ticket is reissued.

Where can a travel agent see the fare rules for a booking?

In the GDS or booking tool, display the rules for the priced fare or the fare basis. Most systems let you request a short summary or the full text, and APIs can return structured data for selected categories such as advance purchase, stays and changes.

Do fare rules change after the ticket is issued?

The rules that apply are normally those in force on the ticketing date. Pricing systems can retrieve historical rules by ticket date, which matters when a customer changes or refunds a ticket months after purchase.

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Sources and further reading

  1. Travelport — Fare Rules (Universal API help)
  2. ATPCO — Breaking down the building blocks of standards
  3. Travelport — Cat25: Fare By Rule