Choosing the right carry-on bag size can decide whether your trip starts smoothly or with an unexpected fee at the gate. Airlines do not share one single limit, and a bag that was accepted last month may be rejected by a different carrier today. This guide compares the verified cabin limits for 59 airlines, so you can see where your bag fits, where it is tight, and where it will not be allowed at all. Before you pack, run your bag through our Baggage Checker for a quick pass or fail against your airline.
The differences can look small on paper, yet a few centimetres matter when a bag must slide into an overhead locker or a metal sizer. Height is usually the tightest dimension, and weight can catch out travellers who only check size. The sections below start with the size most airlines cluster around, then look at the strictest limits, the most generous allowances, and the airlines that use a total-size rule instead of fixed dimensions for each side.
The near-universal cabin size
Most full-service airlines cluster around 55 to 56 cm long, 40 cm wide and 23 to 25 cm deep, in other words roughly 55-56 x 40 x 23-25 cm. Emirates allows 55 x 38 x 22 cm, Lufthansa allows 55 x 40 x 23 cm, and Turkish Airlines also allows 55 x 40 x 23 cm. If your bag is close to these measurements, it will feel familiar on many major airlines, although you should never assume that close enough is the same as within the limit. A centimetre over can still be challenged at boarding, especially on a full flight where locker space is under pressure.
The strictest cabin limits
The strictest limits belong to low-cost carriers, where the free bag is often a small bag that fits under the seat rather than a full cabin case. Wizz Air’s free bag is 40 x 30 x 20 cm, and Ryanair’s free small bag is also 40 x 30 x 20 cm. easyJet’s free underseat bag is slightly larger at 45 x 36 x 20 cm. Travellers used to a standard cabin case are often surprised by how much smaller these free allowances are. If you want a larger cabin bag on these airlines, you normally need a paid option, and that choice is cheapest before you reach the airport.
The most generous
At the other end of the scale, some airlines allow noticeably more room. Southwest allows 61 x 41 x 25 cm, which is larger in every direction than the common cluster. British Airways and Saudia both allow 56 x 45 x 25 cm, giving extra width that can help with a softer bag, although a wide bag still needs to fit the locker safely. Generous limits on one airline do not transfer to another, so a bag bought for the most generous carrier may be too large when you change airlines on the same trip.
Airlines with no fixed size: the 115 cm rule
Some airlines do not publish a fixed size for each side. Instead, Singapore Airlines and Oman Air cap the total of length plus width plus height at 115 cm. That gives you more freedom to choose the shape of your bag, as long as the three measurements add up to 115 cm or less. A long, slim bag and a shorter, wider bag can both pass under this rule if their totals are the same. Add your three numbers together before you travel, and remember that the total is the limit, not a guide.
The table below compares ten well-known airlines side by side. Use it as a starting point, then confirm your own airline and fare before you fly, because cabin allowances can differ by ticket type and the same bag can pass on one carrier and fail on another.
| Airline | Cabin size | Cabin weight |
|---|---|---|
| Emirates | 55 x 38 x 22 cm | 7 kg |
| Qatar Airways | 50 x 37 x 25 cm | 7 kg |
| Lufthansa | 55 x 40 x 23 cm | 8 kg |
| British Airways | 56 x 45 x 25 cm | No published limit |
| Ryanair (free bag) | 40 x 30 x 20 cm | — |
| Wizz Air (free bag) | 40 x 30 x 20 cm | 10 kg |
| Delta | 56 x 35 x 23 cm | No published limit |
| Air Canada | 55 x 40 x 23 cm | 10 kg |
| Singapore Airlines | 115 cm total | 7 kg |
| Qantas | 56 x 36 x 23 cm | 7-14 kg by route |
Cabin weight limits vary more than size
Size gets most of the attention, but cabin weight limits vary even more. They start as low as 5 kg with Air China and rise to 15 kg for easyJet’s paid bag, while the US majors publish no weight limit for cabin bags. That range means a bag that feels light enough at home may still be over the limit for a carrier with a low allowance, especially once you add a laptop, books or other heavy items. Weigh your bag packed, not empty, and leave a small margin below the limit in case airport scales read slightly differently from yours at home.
The safe choice if you fly many airlines
If you fly with many different airlines and want one bag that works almost everywhere, choose a bag at or under 55 x 40 x 20 cm and keep it at or under 8 kg when packed. A bag at that size passes almost everywhere as a main cabin bag, although it will still be too large for the free small-bag allowances of the strictest low-cost carriers. Measure carefully, including wheels and handles, and if your airline changes, test your bag again with the Baggage Checker before you leave home.
Frequently asked questions
What is the standard carry-on bag size?
There is no single official standard, but most airlines cluster around 55-56 x 40 x 23-25 cm. A bag at or under 55 x 40 x 20 cm and 8 kg is a safe choice for many airlines, but you should always check your own airline limit before you fly.
Which airline has the smallest free cabin bag?
Among the airlines in this guide, the smallest free bags are 40 x 30 x 20 cm, offered as the free bag by Wizz Air and as the free small bag by Ryanair. The easyJet free underseat bag is 45 x 36 x 20 cm.
Do airlines weigh cabin bags?
Some do, and limits vary widely, from 5 kg with Air China to 15 kg for the easyJet paid bag. US majors publish no weight limit, but other airlines can check weight at check-in or at the gate, so weighing your packed bag at home is worthwhile.
Ready to check a specific airline? Browse the full Airlines index to find your carrier’s cabin and checked allowances, verified against the airline’s own pages.