Carry-On Size by Airline

Each row links to the carrier’s own published baggage policy and carries the date we checked it. Airlines change these without notice — if you find a figure that has moved, tell us and we will fix and re-date the row.

There is no single American carry-on standard, which is the fact that costs people money. Six of the eleven US carriers above publish 22 × 14 × 9 in. Southwest publishes 24 × 16 × 10 in. Sun Country publishes 24 × 16 × 11 in. A bag bought to fill the Southwest allowance is over the limit on more than half the market, and nothing on the bag will tell you that — manufacturers publish a “case” size that excludes the wheels and a separate “overall” size that includes them, and only the second one is what gets measured.

That gap is not small. One widely sold bag marketed as a 21-inch carry-on publishes a case height of 21 in and an overall height of 23 in. The overall figure is an inch over the limit at American, Delta, United, Alaska, JetBlue and Hawaiian. Measuring a bag the way an airline does takes two minutes and is the single most useful thing on this site.

What these numbers actually govern

The published limit is the size of the box a gate agent can put your bag into. It is enforced at three points, and only one of them is predictable:

• At the bag drop or gate sizer. This is where a bag gets measured, and it is measured as a whole object — wheels, handles, external pockets and any dangling strap.
• At boarding, when the bins fill. A bag that fits the box can still be gate-checked because there is no room. That is not a size rule and no bag protects you from it.
• At the fare, before you fly at all. Four of the eleven US carriers above do not include the overhead bag in their cheapest fare. Size becomes irrelevant if you have not bought the allowance.

The standard box, and who breaks it

The de facto US standard is 22 × 14 × 9 in, published by American, Delta, United, Alaska, JetBlue and Hawaiian. Delta adds a second constraint the others do not: a combined 45 linear inches. Since 22 + 14 + 9 = 45, a bag at exactly the standard box passes on both counts — but a bag that trades an inch of height for two inches of width fails Delta’s linear test even if no single dimension is over.

The practical conclusion is short: buy for 22 × 14 × 9 in, and treat any extra allowance on Southwest, Frontier, Allegiant or Sun Country as a bonus you do not build a purchase around. A bag sized to the largest box in this table fails at the majority of gates.

The carriers where the size does not matter first

Frontier, Allegiant, Breeze and Sun Country all charge for the overhead bag on their cheapest fare. On those airlines the size question is second; the first question is whether you are carrying a bag that fits the free personal-item box instead. Frontier and Allegiant both publish 18 × 14 × 8 in for that, which is a real bag — 30 L of usable volume — and it costs nothing.

International carriers

Three European carriers are included below because they are where American travelers most often get caught. They publish in centimeters and the boxes are genuinely different, particularly Ryanair’s.

Read the Ryanair row carefully. The Basic fare includes only the under-seat bag at 40 × 30 × 20 cm. The 55 × 40 × 20 cm overhead bag requires Priority, which is a paid add-on. A 22 × 14 × 9 in American carry-on is 56 × 36 × 23 cm — over Ryanair’s overhead limit on depth even after you have paid for it.

A carrier that is no longer in this table

Most carry-on size tables you will find online still list Spirit Airlines and its 22 × 18 × 10 in box. That box no longer exists.

We mention it because it is a good test of whether a table is maintained. A page that still lists a carrier that stopped flying in May 2026 has not been checked since before then, whatever date is printed at the top of it.

Per-carrier notes

The numbers do not say everything. These are the things worth knowing that a dimension cannot express.

American Airlines

American measures the full outside size of a carry-on, wheels and handles included.

Delta Air Lines

Delta also caps the carry-on at 45 linear inches (length plus width plus height). It publishes no personal-item dimensions; the rule is that the item fits under the seat in front of you.

United Airlines

United's personal-item box is the tightest of the big three US carriers. Basic Economy on some domestic routes allows the personal item only.

Southwest Airlines

The roomiest published carry-on box of any major US carrier. A bag bought to fill Southwest's allowance will not fit most of the others.

Alaska Airlines

Alaska publishes no personal-item dimensions; the item must fit under the seat ahead of you.

JetBlue

JetBlue states plainly that it has no carry-on weight restriction, but you have to lift the bag into the bin yourself.

Frontier Airlines

One of the few US carriers publishing a carry-on weight limit, and one that charges for the overhead bag. Frontier prints the personal item as 14 in high by 18 in wide by 8 in deep.

Allegiant Air

Allegiant states the measurement includes wheels, pockets, handles and decorations. Only the personal item is free.

Hawaiian Airlines

The tightest published carry-on weight limit in this table, at 25 lb. Several hardside carry-ons weigh a quarter of that empty.

Breeze Airways

The overhead bag is bundled into the Nicer and Nicest fares or bought separately. The personal item is included on every fare.

Sun Country Airlines

A generous published box, but the overhead bag is a paid add-on and carries a 35 lb cap.

British Airways

Published in centimeters: a 56 x 45 x 25 cm cabin bag up to 23 kg, plus a 40 x 30 x 15 cm handbag or laptop bag. The inch figures here are conversions of those published numbers.

Ryanair

The Basic fare includes only the small under-seat bag, 40 x 30 x 20 cm. The 55 x 40 x 20 cm overhead bag needs Priority. The tightest box in this table by a wide margin.

easyJet

Published in centimeters: a free 45 x 36 x 20 cm under-seat bag and a 56 x 45 x 25 cm overhead cabin bag. Inch figures are conversions.