The general rule of thumb is that a carry-on bag should be no larger than 22 inches tall, 14 inches wide, and 9 inches deep. But, let's be real, who actually measures their bag before heading to the airport? It's like trying to eyeball a distance - you think you're close, but you're really not.
A good way to think about it is to consider the size of a standard suitcase. If your bag is significantly larger than that, it's probably too big. And, if you're still unsure, you can always check with your airline for their specific carry-on size restrictions. Better safe than sorry, right?
