Shoe sizes vary so much between brands that buying a new pair can feel like a crapshoot. Obviously, the best way to get a good fit is to just try them on, but that’s not always possible. If you have no choice but to order online, you should know how big your feet actually are in centimeters.
Why centimeters and not inches? Unsurprisingly, they’re more widely-used: Almost every shoe manufacturer on the planet includes centimeter measurements in their sizing charts, so once you know your numbers, you can easily find your size in any brand. It also makes converting men’s sizes to women’s or kids’ (and vice versa) quick and accurate. Basically, if you buy shoes online, you need to measure your feet.
Thankfully, this is super easy to do. The two best methods require a ruler or tape measure, a pen and paper, and someone to help. Centimeter markings are ideal, but it’s OK if you don’t have a metric ruler or tape. Just be sure to multiply each measurement in inches by 2.54 to get the equivalent number in centimeters.
It’s easier to use a soft tape measure because you can simply stand on it and have your assistant compute the difference of your toe and heel position. This video from Good Sports Outdoor Outfitters in San Antonio describes the technique in detail:
If you only have a ruler or something else you don’t want to stand on, you can trace your feet and use that to measure the length. The Michigan Foot Doctors YouTube channel has an in-depth guide to proper tracing and measuring:
Whichever technique you use, make sure you actually put weight on each foot as it’s being measured so you get as accurate a number as possible. Once you’re done, save both measurements in a note on your phone, Google Drive, Dropbox, or password manager. (A Post-it on the fridge works, too.)
Using your measurements really takes the guesswork out of finding your size. Let’s say your left foot is 26.3 centimeters and your right is 26.5. For shoes that need a snug fit and/or will likely stretch out, look for the size that corresponds to 26.5 or 27 centimeters. If you want a roomier fit—such as for boots you’ll wear with thick socks—go for 27.5 or even 28.
That’s it! You may not get the perfect size every single time, but you’ll get a lot closer than you would with traditional number sizes. “Size 9″ can mean a million different things, but you can always trust the centimeter.