One Bag for Every Airline

A 55 × 35 × 20 cm (21.5 × 13.7 × 7.8 in) carry-on fits every airline here, U.S. and European, with a 40 × 25 × 15 cm personal item. On U.S. airlines only, the usual 22 × 14 × 9 in fits them all. Tick your airlines for the biggest bag that passes every one.

How to use it

Tick the airlines you will fly this year, or pick a group: U.S. airlines, the U.S. and Canada, Europe, or every airline here. The answer is the largest carry-on and the largest personal item that pass all of them, in inches or centimeters, with the airline that sets each side, the lowest weight limit among them, and the airlines whose fare does not include a carry-on. Measure a bag you already own with the Airline Bag Size Checker to see it airline by airline.

How it is worked out

A bag fits an airline’s sizer when, with both put in order from the longest side to the shortest, each of the bag’s sides is within the airline’s matching side. So the biggest bag that fits several airlines takes the smallest limit on each side: the shortest “longest side”, the shortest “middle side”, the shortest “shortest side”. Each airline is held to its own number in your unit (American publishes both 22 × 14 × 9 in and 56 × 36 × 23 cm); an airline that gives only centimeters is converted (1 in = 2.54 cm), and every answer is rounded down, never up: 55 cm is 21.65 in, so the answer says 21.6. When an airline also limits the three sides added up (Delta: 45 in), the tool says so if the bag’s own sides add up to more. The limits are the ones the Airline Bag Size Checker read on each airline’s own baggage page.

The groups are the airlines the Airline Bag Size Checker covers: American, Delta, United, Southwest, JetBlue, Alaska, Hawaiian, Frontier, Allegiant and Breeze in the U.S.; Air Canada and WestJet; Volaris in Mexico; British Airways, Lufthansa, Air France, KLM, Turkish Airlines, Aer Lingus, Ryanair and easyJet in Europe. Delta, Southwest, Alaska and Hawaiian publish no personal item size, so they do not narrow it.

Worked examples

U.S. airlines, and one trip on Lufthansa. The 22 × 14 × 9 in carry-on that fits every U.S. airline fails Lufthansa’s 55 cm by a third of an inch; the bag for all eleven is 21.6 × 14 × 9 in.

Ryanair and easyJet. Their fares include the small bag only; the carry-on is paid extra. The personal item that fits both is 40 × 30 × 20 cm; the paid carry-on for both is 55 × 40 × 20 cm.

KLM and Air France. A 55 × 35 × 25 cm carry-on, but they weigh your two cabin bags together: 12 kg for both.

Common mistakes

• Measuring the packing space. The limit is the outside: wheels, handles and pockets count.
• Calling “international” one size. There is no size every airline agrees on; the answer depends on which ones you fly.
• Forgetting the weight. Lufthansa and Turkish Airlines allow 8 kg in the cabin, Aer Lingus 10 kg; U.S. airlines mostly give no carry-on weight.
• A soft bag packed full. It bulges past the sizer’s depth: pack it to the size, not past it.
• The lowest fare. On basic fares some airlines include only the personal item: check yours before you pack for a carry-on.

Pack for it

Fill it with the carry-on packing list every smart traveler swears by, see the luggage cabin crews use, and pack for the trip with the Italy or Japan packing list. Then check what a checked bag costs and your bag’s weight in kilograms and pounds.