18" - 20" Carry-On Luggage
These sizes are considered the International carry-on sizes, as they are allowed to be carried as a carry-on luggage bag for most of the International flights. They are ideal for 1-2 days' trips, as they have packing space for a few travel necessities, such as a pair of shoes, and toiletries.
21" - 22" Carry-on Luggage
These are the most popular sizes for carry-on luggage bag for U.S. domestic flights. Most U.S. airlines have carry on restrictions of 22" x 14" x 9", or 45 linear inches. These are the ideal sizes for business travelers or weekend trips, as most carry on luggage bags of these sizes have either a foldout or removable garment sleeve that can hold an exchange of clothes and has sufficient packing space for a few outfits, a couple pairs of shoes, and toiletries. Most also have an expandable feature, which allows an additional 2 to 4 inches' packing capacity, but please be noted that if it's expanded these sizes may exceed the carry on restrictions and would have to be checked.
23" - 24" Small Checked Luggage
These sizes are popular for those travelers who are looking for a smaller, lighter option of luggage to check. These luggage bags are too large to carry onto the plane, but are perfect for trips of 3 to 5 days. There is enough room for 2 to 3 outfits, a couple pair of shoes, and toiletry kits.
25" - 27" Checked Luggage
These sizes are the most popular size of luggage bags to check. They are ideal for trips of 5 to 7 days, or longer, depending on how you pack. They have a large capacity for multiple outfits, shoes, and toiletries. The suiter (a fold out or removable garment sleeve) can hold two thick wool suits and up to four dresses. These are the best option for luggage bags to check, they have lots of room to pack but you won't break your back trying to move it.
28" - 32" Suitcase
These are very large suitcases bags meant for trips exceeding a week. They have a tremendous capacity for anything you would like to travel with. Due to their large size, when fully packed they can be difficult to maneuver and may exceed the 50 lbs. weight restrictions that most U.S. airlines enforce. Along with the weight restrictions, most U.S. airlines have a size restriction of 62" linear inches and these sizes may exceed that size, especially when it's expanded. But if you know you need the biggest piece of luggage bag available, these would be suitable for you.