Cabin bag size in litres
A 55x40x20 cm cabin bag holds at most 44 litres, and a 40x30x20 cm free under-seat bag at most 24. Across the 29 airlines we track, the most common limits are 55x40x23 cm for the cabin bag and 40x30x20 cm for the free under-seat bag. Litres are only a shortcut: airlines measure centimetres, so the three measurements decide whether a bag fits.
When a bag is sold as “40 litres”, that figure is a capacity, not a size. Two bags with the same litres can be different shapes, and the one that is too deep for the sizer will be stopped. Use the litres to shop, then check the measurements against your airline’s limit.
Turn a bag’s size into litres
Measure the outside of the packed bag in centimetres.
44 litres
The most a 55×40×20 cm bag can hold. A real bag has rounded corners, so expect a little less.
Hand luggage size in litres, by airline
The most each airline’s limits can hold, from its own published sizes (checked 20 Oct 2026). Free under-seat bag is on the cheapest fare; cabin bag may cost extra.
| Airline | Free under-seat bag | Cabin bag |
|---|---|---|
| Aer Lingus | 24 L40 × 30 × 20 cm | 52.8 L55 × 40 × 24 cm |
| Air Canada | 22.7 L43 × 33 × 16 cm | 50.6 L55 × 40 × 23 cm |
| Air France | 18 L40 × 30 × 15 cm | 48.1 L55 × 35 × 25 cm |
| American Airlines | 31.5 L45 × 35 × 20 cm | 46.4 L56 × 36 × 23 cm |
| British Airways | 18 L40 × 30 × 15 cm | 63 L56 × 45 × 25 cm |
| Delta Air Lines | None free | 45.1 L56 × 35 × 23 cm |
| easyJet | 32.4 L45 × 36 × 20 cm | 63 L56 × 45 × 25 cm |
| Emerald Airlines (Aer Lingus Regional) | 24 L40 × 30 × 20 cm | 52.8 L55 × 40 × 24 cm |
| Emirates | None free | 46 L55 × 38 × 22 cm |
| Etihad Airways | None free | 46.4 L56 × 36 × 23 cm |
| Eurowings | 30 L40 × 30 × 25 cm | 50.6 L55 × 40 × 23 cm |
| Iberia | 18 L40 × 30 × 15 cm | 56 L56 × 40 × 25 cm |
| Jet2 | 24 L40 × 30 × 20 cm | 63 L56 × 45 × 25 cm |
| KLM | 18 L40 × 30 × 15 cm | 48.1 L55 × 35 × 25 cm |
| Loganair | None free | 25.2 L40 × 35 × 18 cm |
| Lufthansa | 18 L40 × 30 × 15 cm | 50.6 L55 × 40 × 23 cm |
| Norwegian | 24 L40 × 30 × 20 cm | 50.6 L55 × 40 × 23 cm |
| Qatar Airways | None free | 46.3 L50 × 37 × 25 cm |
| Ryanair | 24 L40 × 30 × 20 cm | 44 L55 × 40 × 20 cm |
| SWISS | 18 L40 × 30 × 15 cm | 50.6 L55 × 40 × 23 cm |
| TAP Air Portugal | 18 L40 × 30 × 15 cm | 55 L55 × 40 × 25 cm |
| Transavia | 24 L40 × 30 × 20 cm | 55 L55 × 40 × 25 cm |
| TUI Airways | 24 L40 × 30 × 20 cm | 44 L55 × 40 × 20 cm |
| Turkish Airlines | 18 L40 × 30 × 15 cm | 50.6 L55 × 40 × 23 cm |
| United Airlines | 23.7 L43 × 25 × 22 cm | 45.1 L56 × 35 × 23 cm |
| Virgin Atlantic | 18 L40 × 30 × 15 cm | 46.4 L56 × 36 × 23 cm |
| Volotea | 24 L40 × 30 × 20 cm | 55 L55 × 40 × 25 cm |
| Vueling | 24 L40 × 30 × 20 cm | 44 L55 × 40 × 20 cm |
| Wizz Air | 24 L40 × 30 × 20 cm | 50.6 L55 × 40 × 23 cm |
Volumes are the maximum for a box with exactly the airline’s three measurements. Real bags have rounded corners and soft sides, so they hold a little less.
Cabin bag litres: common questions
How do I convert a bag’s size in cm to litres?
Multiply height × width × depth in centimetres and divide by 1,000. A 55×40×20 cm bag is 55 × 40 × 20 = 44,000 cubic centimetres, which is 44 litres. That is the biggest it can be; bags with rounded corners hold less.
How many litres is hand luggage?
It depends on the airline. Across the 29 airlines we track, the cabin bag limits work out at 25.2 to 63 litres of box volume, and the free under-seat bag limits at 18 to 32.4 litres.
Is a 40 litre bag allowed as a cabin bag?
On volume alone, 28 of the 29 cabin bag limits we track have room for 40 litres. In practice many bags sold as 40 litres are taller or deeper than the limit once packed, so compare the three measurements, not just the litres.
Is a 20 litre bag allowed as a personal item or under-seat bag?
15 of the 24 free under-seat bag limits we track have room for 20 litres. Under-seat limits are the tightest, so a 20 litre bag must also be flat enough: depth is usually the problem.
Do airlines check litres or centimetres?
Centimetres. Gate staff use a metal sizer frame, not a label, so a bag that is within the three measurements passes whatever its litre rating says.
Ready to test a bag? Check it against your airline or compare every airline’s sizes.