Smaller is better when it comes to carry-on luggage because depending on the airline, the size regulations vary.

“People often want to use a carry-on so that they don’t have to pay to check in a bag. It also saves time at check-in, and you can bypass baggage claim,” said Nikhil Hutheesing from Consumer Reports.

The maximum dimensions for a carry-on for most U.S. air carriers is 14 inches wide by 22 inches high by nine inches deep - but if your bag doesn’t fit, it might not be your fault. New Consumer Reports testing has shown some bags are not as small as manufacturers claim. 

Experts put 11 bags to the test, measuring each one several times with laser precision. Nine of the 11 were bigger than they claimed; including bags from American Tourister, Samsonite, TravelPro and Victorinox. 

“We found that many manufacturers don’t count things that affect the dimensions of a bag –– like the wheels and the handles. But the expectation is, that when you buy a carry-on bag, it’s going to fit in the overhead bin,” Hutheesing said. 

Testing of a Tumi Alpha-2 Frequent Traveler showed the measurements to be accurate but still several inches too large to be carried on most airlines. Different airlines may also have different restrictions. 

Canada’s major airlines allow carry-ons slightly bigger than most U.S. carriers and depending on size, that could mean what’s allowed as a carry-on in Canada might have to be checked if you’re transferring to a U.S. carrier. 

Air Canada allows 15.5 inches wide by 21.5 inches high by 9 inches deep while WestJet’s allowance is 15 inches wide, 21 inches high by 9 inches deep. 

A recent International Air Transport Association initiative to introduce an optimum size of 14 by 22 x 9 for all airlines has been put on hold because of resistance by air carriers to set a standard size. 

Air Canada told us it has no current plans to change its carry-on baggage allowance or dimensions. 

Consumer Reports recommends that you pack with care, particularly outside pockets. Overstuffed can easily become oversized! Because one thing is universal: If it doesn’t fit, you must check it!