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Unless you're a 10-year-old who's starting to outgrow your last pair of shoes, you probably already know your exact shoe size. But even when you reach adulthood, your feet actually continue to grow larger and flatten out through the course of your lifetime. So it doesn't hurt to re-measure... you might have grown a half-size or more! It's very important to measure the width of your foot, too, since you can't try on shoes in advance when buying online.

A Brannock Foot-Measuring Device®, that funny metal instrument in shoe stores that looks like a combination between a ruler and a medieval torture device, is designed to measure the length and width of your foot to determine your optimal shoe size. This device is usually only used on children whose feet are still growing, since kids' shoe sizes change so rapidly. Yet adults need to occasionally double-check their own foot sizes.

See more information.

Many shoe stores now leave a Brannock Device® available on the floor for customer use, so the next time you see one lying around take a few minutes to verify the length and width of your feet. For online printable versions of the Brannock, click these links WOMENS / MENS / KIDS.

Here's how to use this measuring tool:

Remove your shoes but be sure to leave on a pair of fitted socks.

Heel-to-Toe Length: While standing up or sitting down with your feet parallel to the floor, place one heel firmly against the appropriately labeled end of the device.

Record the size indicated at the tip of your longest toe (the longest point of your foot).

Arch Length: Place your thumb on the ball joint of the foot (the inside part of your foot where your big toe meets your foot) and slide the arch-length pointer to where it is centered on the protruding ball joint of your foot. Record this size also (it may be different than your overall foot size, and is very important since shoe sizes are generally built based around heel-to-ball length).

Width: Slide the width bar against your foot and record your foot width (ranges from 3A to 3E). This is done by locating your shoe size on the moveable width bar and matching it up with the corresponding width measure.

Men have a medium width of D, a narrow width of B, a wide width of E and an x-wide width of 3E.

Women have a medium width of B, a narrow width of A, a wide width of D and an x-wide width of EE.

If the size falls between two widths, choose a wider width for a thick foot, a narrower width for a thin foot.

Now that you’ve got all three measurements (heel-to-toe length, arch length and width), compare the arch length to the heel-to-toe length. Choose the larger of the two measurements as the correct shoe size for your foot.

Repeat entire measuring process for your other foot, but remember to rotate the Brannock device 180 degrees first. Very few people have feet that exactly match one another, and you need to buy shoes based on your larger foot size.

The reason you want to measure your foot length two different ways is that your best shoe size is probably the longer of your total foot length and arch length. Also, it's good to know your foot width, since all widths are all clearly labeled at SierraTradingPost.com

For men, D is a "medium width.” For women, B is considered a “medium width.” Higher letters indicate a wider foot, and lower letters a narrower one. Men have a medium width of D, a narrow width of B, a wide width of E and an x-wide width of 3E and up. Women have a medium width of B, a narrow width of A, a wide width of D and an x-wide width of 2E and up.

Despite the usefulness of a Brannock Foot-Measuring Device®, realize that whatever shoe size feels best is best. If the Brannock says you're a size 11 D, but you like the feel of a size 12 E, go with the 12 E.