nettereo16
WKR
And even if you exceed it they'll likely only make you just gate check it (pick up in the jetway) or check it through (pick up at baggage claim).Generally speaking, if H+W+D=48" or less, it meets requirements for carry on bags in overhead bins.
You may want to double check with your specific carrier.
Not a huge deal either way and a good way to beat expensive bag fees and not worry about finding a spot to stuff it in the overhead!