What is legal size for carry on bag for a plane?

The legal size for a carry-on bag typically varies by airline, but most airlines allow dimensions of around 22 x 14 x 9 inches (56 x 36 x 23 cm), including handles and wheels. It's important to check the specific airline's guidelines before traveling, as some may have stricter size limits or weight restrictions. Additionally, many airlines permit a personal item, such as a backpack or purse, that fits under the seat in front of you.