How to convert your shoe size to shop multiple styles

When finding footwear, figuring out what size to buy is often more complicated than “if the shoe fits, wear it.” And you know from your own closet that you might take a larger size in closed shoes and sneakers than you do in sandals or pumps.

The shoe size question is particularly onerous when companies sell shoes labeled as “men’s,” “women’s,” and “unisex," as the sizing scales are not the same for each "gender" of shoes. But knowing the size you take in each could expand your shoe shopping options significantly, especially if you prefer to order footwear online.

So before you put your best foot forward in a new pair of kicks, keep these expert sizing and fit tips in mind.

Why do shoe sizes vary?

Shoes are constructed around a form called a “last,” which determines the shape and size of the shoe. As for why a size 7 in one brand doesn’t fit the same as another? It all comes down to the last’s design. “The lasts all have a little bit of a different shape,” explains Jim McFarland, historian of the Shoe Service Institute of America, noting that shoemakers often have “hundreds of lasts,” depending on how many sizes and widths are offered in each shoe.

What's more, some brands essentially shrink down the men’s size lasts to create women’s size ones, while others design separate lasts for the different sizing categories, such as Lululemon with its new Blissfeel running shoe, which the brand tailored to features more common to female feet.

Features like a pointy toe, round heel, and so on might also impact how shoes fit your foot. “It’s going to be trial and error learning what [styles] fit you the best in what sizes,” McFarland adds.

How can you convert men’s and women’s shoe sizes?

Don’t be deterred by the gendered shoe sizing system, as it’s possible to find the right fit for most feet in most styles regardless of whom the brands think they’re marketing to. If a shoe you want to buy isn’t available in your usual "gender," it doesn’t take much math to convert between men’s and women's sizes.

To go from men’s shoe sizes to women’s, McFarland recommends adding 1.5 or 2 sizes (i.e., a men’s size 7 is approximately a women’s size 8.5 or 9). But you’ll also need to keep width in mind. Shoes typically come in three widths: narrow, medium, and wide (although it's getting harder to find narrow shoes these days as “the money is in medium and wide,” McFarland says). If you typically wear men’s size shoes and are purchasing a women’s size shoe, he recommends opting for a wide, given that women’s shoe sizes tend to run narrower. To go from women’s to men’s shoe sizes, it's best to subtract just 1.5 sizes (i.e., a women’s size 8 is approximately a men’s size 6.5), McFarland says. This lets you compensate for the more narrow fit of women's shoes.

The exception, however, is for individuals who have very small or very large feet. In those cases in particular, you should take note of what size range the brand sells. For example, the smallest men’s size New Balance sells is a 5.5 or equivalent to about a women’s 7, for instance, whereas Saucony's largest size in the women's scale is 13, or about a men's 11.

How to convert women’s shoe sizes to youth sizes

Youth-sized shoes typically run from 3.5 to 7 on the men’s scale. To go from women's sizes to youth sizes, you subtract 1.5 or 2. Therefore, youth shoe sizes should work for anyone who wears between a 5 and an 8.5 in women’s size shoes—a budget boon for adults with smaller feet, as kids’ kicks often feature similar designs for a lower price tag.

Are unisex shoe sizes the same as men’s?

Most unisex shoes follow the men’s sizing scale. That means your unisex shoe size is either your men’s shoe size or your women’s shoe size minus 1.5 or 2. That said, unisex shoes may be built around a last that’s narrower than the typical men’s shoe, so you should take that into account if you have wider feet.

How can you measure your shoe size?

The most accurate way to measure is with a Brannock device, i.e., the metal sliding shoe sizer in most shoe stores, says McFarland. But to measure your foot at home, stand on top of a piece of paper with your heel against a wall, then have someone else mark the end of your toe. (The reason: Your foot shape and position can change when you bend down.) Jot down the heel-to-toe length for each foot, and find your corresponding size on a size chart, opting for the size that will more comfortably fit your larger foot.

How do you find shoes that fit?

Regardless of what the measurements tell you, it’s best to try shoes on before you buy, because of that lack of standardization among brands and those style factors such as toe shape and the amount of coverage of the upper.

If you’re still having trouble determining the best size for your foot, however, don’t hesitate to reach out to a brand’s customer support for more sizing information, especially if your feet are narrow or wide. “They should know their last and which shoes are going to be shaped for [your] type of foot,” says McFarland.

Finally, if you prefer shop online, check the return policies. Some large shoe retailers, such as Zappos and Nordstrom, offer free shipping and free returns, while others, such as DSW and L.L. Bean, offer free returns in-store, should you flip a coin on your size and guess wrong.

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Prices were accurate at the time this article was published but may change over time.