RASK vs CASK: meaning & airline data

RASK means revenue per available seat kilometre; CASK means cost per available seat kilometre. Together, they show the revenue and cost an airline reports for each unit of seat capacity. Use the formulas and worked example below, then explore company-reported figures in the airline table. Definitions, business scope and reporting periods can differ, so check each airline profile before comparing results.

Unit revenue and unit cost across all airlines

Every airline in the database is listed below with the unit-revenue, unit-cost and capacity measures it discloses; where a carrier does not publish a measure, the table says so rather than estimating it. The exact metric and period disclosed varies by carrier, so the source notes on each page should be read before making direct comparisons.

Why RASK and CASK comparisons can mislead

• Stage length: longer average sectors usually reduce cost per ASK even when the absolute cost of a flight is higher.
• Load factor: RASK can move even when yield is stable because more or fewer seats are filled.
• Ancillary revenue: carriers differ in how non-ticket revenue is included and disclosed.
• Network mix: long-haul, short-haul, connecting and point-to-point models are structurally different.
• Currency and fiscal periods: reported trends may cover different calendars and currencies.
• Company definitions: adjusted, ex-fuel and ex-ETS measures are not always calculated consistently.

Use unit economics with profitability and traffic

RASK and CASK are most useful when read together with load factor, yield, operating margin and fleet growth. A carrier can improve load factor while worsening profitability if fares or unit revenue fall faster than costs, and a higher CASK is not automatically negative if it accompanies stronger RASK.

Continue with the Airline Comparison tool, the Airline Operating Margins hub, the Airline financial results database, or browse the full Airline Intelligence database.

RASK and CASK: common questions

What does RASK stand for?

RASK stands for revenue per available seat kilometre. It is an airline’s revenue divided by its available seat kilometres (ASK), usually quoted in cents. US airlines report the same measure per mile, as RASM or TRASM.

What does CASK stand for?

CASK stands for cost per available seat kilometre: operating costs divided by ASK. The US equivalent is CASM.

How do you calculate RASK and CASK?

Divide revenue (for RASK) or operating costs (for CASK) by available seat kilometres for the same business and period. In the worked example above, €12 billion of revenue and €11 billion of costs over 100 billion ASK give a RASK of 12 euro cents and a CASK of 11 euro cents.

What does the gap between RASK and CASK show?

The difference is the operating result per unit of capacity. A spread of 1 euro cent on a RASK of 12 cents is an operating margin of about 8.3%. When CASK is higher than RASK, the airline loses money on its operations.

What is the difference between RASK, PRASK and TRASK?

PRASK counts passenger revenue only. RASK, sometimes called TRASK or total RASK, also includes ancillary, cargo and other revenue. Airlines use these labels differently, so check each company’s definition before comparing.

Why do airlines report CASK excluding fuel?

Fuel costs move with oil prices and hedging, so CASK ex-fuel shows how the rest of the cost base is changing. Fuel is still a real cost: profitability depends on total CASK.

What is a good RASK or CASK?

There is no universal benchmark. Flight length, seat density and business model all move both measures, so compare airlines with similar networks and read the spread and operating margin rather than either number alone. The table above shows company-reported figures for more than 100 airlines, and the break-even load factor explainer shows how the spread translates into how full aircraft need to be.

How is RASK related to yield and load factor?

Passenger RASK equals passenger yield (passenger revenue per revenue passenger kilometre) multiplied by load factor. A fuller aircraft sold at lower fares can therefore produce the same or lower unit revenue.

Research using these metrics

Company-reported airline unit revenue, unit cost and capacity measures, including RASK, CASK and ASK, with definitions, reporting periods and source links.

• How to read airline results: metrics that reveal growth quality
• Why airline load factor can be a terrible measure of performance
• One quarter, three outcomes: Ryanair, easyJet and Wizz Air in the June quarter

Browse all datasets and methodology · Explore the research library

Licence: the data on this page is published under CC BY 4.0. You may reuse it, including commercially, with credit to Aviation Intelligence (gpaviationintelligence.com). Underlying figures come from the companies' own published reports.