The standard carry-on luggage size for the big US airlines is 22 x 14 x 9 inches, including handles and wheels: American, Delta and United all list it. In centimetres it's not quite the same, because American converts it to 56 x 36 x 23 cm while Delta and United use 35 cm for the width. European low-fare airlines are smaller: easyJet's free cabin bag is 45 x 36 x 20 cm and must fit under the seat. Buy a bag that fits the smallest limit you'll fly.
Carry-on rules are one of the easiest ways to start a trip badly, because the numbers look the same until you read the small print. I read the carry-on pages of American Airlines, Delta, United and easyJet. Here's what each one allows.
Carry-on and personal item limits compared
| Airline | Carry-on bag | Personal item | Note |
|---|---|---|---|
| American Airlines | 22 x 14 x 9 in (56 x 36 x 23 cm), including handles and wheels | 18 x 14 x 8 in (45 x 35 x 20 cm) | Must fit the airport sizer |
| Delta | 22 x 14 x 9 in (56 x 35 x 23 cm), and no more than 45 linear inches (114 cm) combined | Fits under the seat in front | 1 carry-on and 1 personal item free |
| United | 9 x 14 x 22 in (23 x 35 x 56 cm), including handle and wheels | 9 x 10 x 17 in (22 x 25 x 43 cm) | Not included in Basic Economy |
| easyJet | Large cabin bag 56 x 45 x 25 cm, only if you've booked one | Small under-seat bag 45 x 36 x 20 cm, free for everyone | Up to 15kg; you must be able to lift it |
The centimetre catch
All three US airlines quote 22 x 14 x 9 inches, but their conversions differ. American lists 56 x 36 x 23 cm, while Delta and United both use 35 cm for the 14-inch side. If you're buying a bag in centimetres, aim for 35 cm or less on that side and it'll meet all three. Delta adds a second test that catches some soft bags: length, width and height combined can't be more than 45 linear inches, or 114 cm.
Personal items are where airlines differ most
The bag under the seat varies far more than the one overhead. American allows a personal item up to 18 x 14 x 8 inches, while United's limit is 17 x 10 x 9 inches, so a backpack that's fine on American can be too big on United. American also lists items that don't count as either bag, such as a diaper bag for each child, a breast pump and child safety seats.
What doesn't count towards your allowance
Airlines let you bring a few extras on top of your two bags. United's page lists a jacket or coat, an umbrella, things to read, food bought at the airport and a camera among the items you can bring for free. American says a soft-sided garment bag can't exceed 51 inches in total dimensions, length plus width plus height. Delta's examples of a personal item are a purse, briefcase or laptop bag, or something of similar size that fits under the seat in front of you.
When you can't bring a full-size carry-on
- United Basic Economy: United's page says the one carry-on plus one personal item allowance applies when you're not travelling in Basic Economy.
- Small regional jets: Delta says flights on Delta Connection aircraft with 50 seats or less only allow personal items on board.
- American Eagle regional flights: American says that if your carry-on is bigger than the personal item size, you'll valet it at the gate, where it's tagged and checked for you at no charge.
- easyJet without a large cabin bag booked: only the small under-seat bag comes on board.
For what to pack in it, here's my business trip packing list for carry-on travel, and my guide to travel backpacks covers bags that work as a personal item.
My advice on choosing a carry-on
Buy to the strictest airline you fly, measuring with the handles and wheels included, because that's how every airline here measures. For US trips, 22 x 14 x 9 inches with a 35 cm width covers American, Delta and United. If you fly European low-fare airlines, a bag that fits 45 x 36 x 20 cm will go free on easyJet and saves you booking a large cabin bag. Check your fare type before you pack, since Basic Economy and small regional jets change the rules.
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Frequently asked questions
What is the standard carry-on size?
American, Delta and United all list 22 x 14 x 9 inches, including handles and wheels. In centimetres, American says 56 x 36 x 23 cm, while Delta and United use 35 cm for the width.
What size is easyJet's free cabin bag?
easyJet says everyone can bring one small under-seat bag of up to 45 x 36 x 20 cm, including handles and wheels, weighing up to 15kg.
What size is a personal item on United?
United's limit for a personal item is 9 x 10 x 17 inches, or 22 x 25 x 43 cm.
Does Delta have a linear inch limit for carry-ons?
Yes. Delta says the combined length, width and height must not exceed 45 linear inches, or 114 cm.
Can I bring a carry-on in United Basic Economy?
United's page says the carry-on and personal item allowance applies if you're not travelling in Basic Economy, so check your fare before you pack.
