Every airline publishes a carry-on size, and almost every one is different. Miss it by an inch and you are handing over a bag at the gate and paying a fee. We built First Class Passport so you can settle the question before you leave home: enter your bag, pick your airline, and see a straight answer with the measurements shown.
Accuracy is the product
A wrong dimension here gets a real traveler's bag rejected, so we treat the numbers like they matter. Every carry-on size, personal-item size, and bag fee is taken from the airline's own baggage page, cited with a link, and dated. We never copy numbers from travel blogs or from memory, and we show you the source on every airline page.
How the checker works
The tool compares your bag to the allowance the same way an airport sizer does: largest side to largest side, so it does not matter which way you turn the bag. It shows the clearance on each side, flags a borderline fit that a full overhead bin could still turn away, and tells you whether the bag also counts as a personal item.
How we stay free
When a bag is over the limit, we point you to carry-ons that do fit, using Amazon affiliate links. If you buy through one we may earn a small commission at no extra cost to you. It keeps the tool free and never changes an answer. See our full disclosure for details.
Airlines change their baggage rules often, so we re-verify on a schedule and stamp each page with the date it was last checked. Always confirm the current policy with your airline before you fly.