FlyerfolioMiles and membership
English

Status: checked against official sources; automated independent review

FREQUENT FLYER GLOSSARY

What are base miles?

Base miles are the miles a programme credits for the qualifying activity itself — an eligible flight or other qualifying transaction — before anything is added on top for elite status, cabin, a partner arrangement or a purchase. American refers to base miles earned for eligible flight activity and says that purchased bonus miles post separately from them [1]. British Airways applies its tier bonus as extra Avios on top of the base flight award when a ticket's fare is not available [3]. Delta publishes a per-dollar earning rate that changes with the experience purchased and with the member's Medallion tier [2].

Facts checked: 18 October 2026

Key takeaways

  • Base miles are the figure earned for the qualifying activity itself; anything added for status, cabin, a partner arrangement or a purchase sits on top of it [1] [3].
  • Bonus miles are often treated differently from base miles. American's purchased bonus miles are non-refundable and non-transferable and do not count toward elite status qualification or Million Miler status [1], and Delta says its Delta Vacations bonus miles do not count toward Medallion qualification or Million Miler status [2].
  • Status uplifts are expressed in different ways: American lists 40%, 60%, 80% and 120% more miles and Loyalty Points for members with AAdvantage status [1], Delta raises its per-dollar rate by Medallion tier [2], and British Airways either builds the tier into a per-pound rate or adds 15%, 30% or 50% to the base flight award [3].
  • What sits inside the base differs by programme: Delta counts base fare and carrier-imposed surcharges but not government taxes and fees [2], while British Airways counts the fare and certain paid add-ons but not non-airline taxes and fees [3].

Why the base portion matters

An earning rate can only be compared with another once the reader knows what the base covers and what is added afterwards. On British Airways-marketed flights where the fare is available, the amount collected is based on the price of the ticket and eligible add-ons, multiplied by tier: Blue members collect 6 Avios per pound, Bronze 7, Silver 8 and Gold 9 [3]. For those bookings the tier difference appears inside the per-pound figure rather than as a separate bonus [3].

The mechanics change when the fare is not available — including flights booked as part of a British Airways Holidays package, some partner flights and some bookings through travel agents. Those tickets collect Avios based on a percentage of the miles flown and the cabin flown, and Bronze, Silver and Gold members then collect tier bonuses of 15%, 30% or 50% extra Avios on top of the base flight award [3]. The base award is therefore the number a percentage bonus is applied to, and British Airways points members to its flight calculator for these bookings [3].

Delta's published rates work from spend. General SkyMiles Members earn 5 miles in Classic or Refundable and 7 miles in Extra per $1 spent on Delta-marketed flights, and 2 miles per $1 with Delta Basic experiences [2]. The page then lists 7 miles per $1 for Silver, 8 for Gold, 9 for Platinum and 11 for Diamond Medallion members, based on the status held at the time of travel [2].

American describes members with AAdvantage status earning more miles and Loyalty Points when they travel with American, oneworld and partner airlines, and lists four uplift levels of 40%, 60%, 80% and 120% [1]. Those uplifts sit on the flight activity that produces base miles [1].

What counts inside the base

American. The earning page checked refers to base miles earned for eligible flight activity and says bonus miles bought through AAdvantage Mileage Multiplier post to the member's account separately from them [1]. It also describes a floor: if the base miles associated with a member's flight are less than 500 miles, the member is offered the option to purchase a minimum of 500 bonus miles [1].

Delta. Miles are earned by the member who is flying, whoever purchased the ticket, and the ticket price eligible to earn miles includes base fare and carrier-imposed surcharges but excludes government-imposed taxes and fees [2]. Delta Main Basic tickets do not earn miles, and partner flights and certain exception fares earn differently [2].

British Airways. Avios are collected on British Airways-marketed flights from the fare, carrier charges the airline may add, cabin upgrades, seats that are pre-booked and paid for, and additional baggage — described on the Avios statement as total eligible spend [3]. Non-airline taxes and fees, such as airport charges and government taxes, don't collect Avios [3]. Reward Flights, agency discounted fares and industry discounted fares are excluded [3]. If Avios are used to part pay a cash ticket, Avios are collected on the full ticket price before the discount, whereas a discount or voucher code means collecting on the price after the discount [3]. Where the amount spent is in another currency, it is converted to GBP using the IATA five-day exchange rate that applied on the day of purchase [3].

Base miles against bonus and promotional miles

Bonus miles can arrive from a purchase, a partner offer or a promotion, and they usually sit outside the base. American's Mileage Multiplier lets a member buy bonus miles on an eligible trip; the purchased miles are non-refundable and non-transferable, typically post within 48 hours of purchase, post separately from base miles earned for eligible flight activity, and do not count toward elite status qualification or Million Miler status [1]. Subsequent changes to a flight, including cancellation or routing changes, do not affect the posting of purchased bonus miles [1]. Amounts charged include US federal excise tax, currently 7.5%, and Canadian GST/HST as applicable [1].

Delta's travel products illustrate the same split. Delta Vacations bonus miles are posted as a bonus and do not count toward Medallion qualification or Million Miler status, and the bonus is 1,000 miles for bookings up to $4,999, 5,000 miles for $5,000 to $9,999, and 10,000 miles for bookings of $10,000 or more, capped at 10,000 bonus miles per qualified customer [2]. Miles awarded for stays booked through Delta and for car rentals booked through Delta are also described as bonus miles and do not count toward Million Miler status [2].

On partner airlines, British Airways sets the base award as a percentage of miles flown and decides separately whether a tier bonus applies. For Aer Lingus and Emerald Airlines, economy lowest booking classes earn 25% and economy flexible classes 100% of miles flown, with no tier bonus [3]. Finnair awards carry a tier bonus of 10% extra for Bronze, 15% for Silver and 25% for Gold, while Japan Airlines carries 25%, 50% and 100% on international flights and the bonus does not apply on Japanese domestic flights [3].

Exceptions and limits

  • Distance-based bases. Where British Airways cannot use the fare paid, the base award is a percentage of miles flown and cabin rather than spend, so the same cash price can produce a different number of Avios [3].
  • Minimum awards. Several British Airways partner tables list a minimum of 500 Avios that may vary in discount economy, and some partners have no minimum [3].
  • Tickets that earn nothing. Delta Main Basic tickets do not earn miles [2]; British Airways excludes Reward Flights, agency discounted fares and industry discounted fares [3].
  • Base below the floor. American's option to buy a minimum of 500 bonus miles applies only where the base miles associated with a flight are below 500 miles [1].
  • Tier bonuses are not universal. British Airways lists no tier bonus for most partner airlines in the tables checked, and excludes Japan Airlines domestic flights from its tier bonus [3].
  • Status credit is separate. American's purchased bonus miles do not count toward elite status qualification or Million Miler status [1], and Delta's bonus miles from vacations, stays and car rentals do not count toward Million Miler status [2].

Sources

Sources checked on 18 October 2026. Only American AAdvantage, Delta SkyMiles and The British Airways Club are covered here; other programmes, including Miles & More, United MileagePlus, Flying Blue and Aeroplan, are not covered on this page.

  1. Earn on American Airlines – AAdvantage program, checked 18 October 2026
  2. How to Earn Miles – Delta SkyMiles, checked 18 October 2026
  3. Collecting Avios on flights – The British Airways Club, checked 18 October 2026