Excess Carry-on Baggage Fee Began October 1, 2015

[SarahZ]

The airlines have baggage sizers, like this, that your bag must fit into.

If you have a hard-sided carry-on, there's no way to force it. Duffels and softer suitcases can be squished to fit the dimensions.

Always remember to include the wheels when measuring, unless you have the type that retract into the suitcase.

 

[BCL]

Correct me if I'm wrong, but don't the airlines base their bag measurements on linear inches?

Only if it's checked in. 62 linear inches seems to be the common standard these days. However, there are some low-cost carriers that limit it to 40 lbs - like Spirit.