I’m confused about what actually constitutes ‘carry-on’ size. For many years I usually flew Southwest which has a larger carry-on limit (24x16x10 I believe). I’m going to be flying Delta and United, they and most other airlines are limited to 22x14x9. I assume that includes wheels and handle.

So I started looking at new luggage sold as ‘carry-on’ but the actual diminsions are slightly bigger that 22x14x9. For example, one sold as 21” luggage has an actual size of 22.5x14.5x9.5. Another, an American Tourister 21” is 23.2x15.5x9.5.

Will I get away with one of these? And is there any point buying one if they’re not actually smaller than what I already have? (the best one I have is 22x14x8 not counting wheels and handle).

They all are pretty clear that the dimensions include the wheels (handles usually collapse). The risk you take is that you will not be allowed to carryon your oversized roller bag. Sometimes they check and sometimes not. With flights all being 100% full now is probably not the time to risk it.

You are correct that some of the advertised dimensions don't include wheels but often you can find that information if you dig a little. My usual carryon for the airlines with smaller sizes is a softsided gym bag although I do own a very small roller bag bought long ago for international travel that meets the stricter dimensions.

If it is listed as a 21 or even a 22 inch rollaboard it will be allowed on any US-based airline even if it is a skosh over the size limit. (Except for the smaller commuter-type planes where they are often gate checked) So on 737's, Air Buses, 777's, etc. they are OK. However a lot of overseas-based airlines have stricter/smaller carry on limits and actually measure the bags in a sizer box, and some also weigh carry ons.

Not gonna make it on most Delta Connection flights that I've used to get from SLC to LGB. I guess those are "commuter-type".

Since Delta's official size rule is 45 linear inches (22 x 14 x 9 in) or 115 centimeters (56 x 36 x 23 cm) they would only be gate checked if the overheads are too small, or if the flight is totally full and there is not enough space in the overheads.

Most planes on the Delta SLC/LGB route are Embraer 175s which are small commuter type planes with less overhead space (the overheads on the right side are 'normal sized' and will hold regulation size carry ons, while the left side is smaller and will not hold full sized carryons. So they very often ask everyone traveling in Economy/coach to check or gate check larger carryons since the limited overheads fill up fast. Flying in Business they don't usually require gate checking since there are only 12 seats (1 - 2 configuration) and there is plenty of space on the right side for 12 carry on's

Thanks to everyone for taking the time to reply. My upcoming flights are cross-country on bigger planes. I don't mind being gate-checked, I just don't want to pay the exorbitant fee for checking a bag (on top of the exorbitant fee I've already paid for the airfare). I guess the consensus is either I take a chance with one of the bags I have, or buy one that's unquestionably small enough. Happy trails, everyone!

If there are estate sales near you, go with a tape measure. You may find a complying bag for $5-$10.

If I am going home, I'd take a chance on a gate check although anything fragile or essential goes in my "personal item" small soft sided bag.

I think the first one you listed would usually be ok, but not the second. Usually it can depend a lot on how full the plane is. I've had my "legal" bag not allowed on a US based airline at one airport and it was allowed in another and both were big planes, so you never know. It can depend on how picky the gate agent is which relates to how full they are, I think.

If you just don't want the fee, I'd just go with any 22 incher and then gate check it if necessary, why not. They always check that at the gate now that there is self-checkin, seems to me (the size).