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Carry-on size is not one size: what 36 airlines actually allow

Published October 15, 2026

There is no standard carry-on size. Among the 36 airlines we track, the cabin-bag limit ranges from 55 x 40 x 20 cm at Ryanair to a simple 115 cm total at Singapore Airlines, and that gap decides whether a bag gets on board. Of the 1,902 bags in our catalog, 1,051 fit Ryanair’s limit and 1,682 fit Singapore’s. Only 864 fit all 36.

If you fly more than one airline, the limit that matters is the strictest one on your trip, not the one printed on the bag’s tag.

The 14 different limits, from strictest to most generous

Many airlines share a limit, so the 36 carriers boil down to 14 sizes. The last column is how many of our 1,902 bags fit that size, in any orientation.

The 22 x 14 x 9 inch size that most US airlines use sits in the middle of the pack: 1,353 of our bags fit it. A bag built for it can still be turned away in Europe and the Gulf.

Depth is the dimension that decides

When a bag is too big, depth is almost always part of the problem. Of the 851 bags that miss Ryanair’s limit, 788 (93%) are too deep, and for 507 of them depth is the only issue. The strictest airlines cap depth at 20 cm (7.9 in) where most others allow 23 cm (9 in) or 25 cm (9.8 in).

Compare Delta and Ryanair. 331 bags fit Delta’s 56 x 36 x 23 cm limit but not Ryanair’s 55 x 40 x 20 cm. For 319 of them, the only problem is depth: they are between 20 and 23 cm thick. The reverse happens too, but rarely. Only 29 bags fit Ryanair and not Delta, all because they are wider than Delta’s 36 cm.

So when you compare two “carry-on” backpacks, look at the smallest of the three numbers first. A 22 cm deep bag is fine on Delta, American and Lufthansa, and turned away by Ryanair, Vueling and Air India.

Total-length limits are more forgiving than they look

Four airlines use a total of length plus width plus depth, 115 cm (45 in). Singapore Airlines uses only that rule, which is why it fits the most bags in our catalog: a long, thin bag and a short, fat one can both pass. Air India, IndiGo and ANA apply it on top of a box size, so for them the box is usually the limit that bites.

The size is not the whole rule

Some of these sizes only apply if you pay. easyJet’s 56 x 45 x 25 cm is its large cabin bag, which costs extra unless you have easyJet Plus or an Inclusive Plus fare; the free allowance is a 45 x 36 x 20 cm bag under the seat. Ryanair’s 55 x 40 x 20 cm bag needs Priority & 2 Cabin Bags, and every fare includes only a 40 x 30 x 20 cm under-seat bag.

Fifteen of the 36 airlines leave the cabin bag out of their cheapest fare. We list them in which airlines make you pay for a cabin bag.

Weight is the other half. Nine airlines, all in Asia-Pacific and the Gulf, cap the cabin bag at 7 kg (15.4 lb), and three of them count your personal item in those 7 kg. We look at what that leaves you in packing for a 7 kg cabin limit.

How to use this

1. List every airline on your trip, including the return and any connection.
2. Take the strictest limit from the table above.
3. Filter the catalog by those airlines, or check a bag you already own with the fit check.

Every bag in our catalog that fits all 36 airlines is 20 cm deep or less, and none of the backpacks is bigger than 39 litres. We look at the trade-offs in the biggest backpack that fits every airline.

How we counted

Limits come from each airline’s own baggage page, linked on its airline page and checked in September 2026. Bag dimensions are the ones each brand publishes. A bag fits when its three dimensions, sorted from largest to smallest, are each within the airline’s sorted limit, so orientation does not matter. Soft bags can squeeze a little; packed ones can bulge. When a bag is within 2 cm of a limit, our bag pages flag it as a tight fit. Full details are in the methodology.