How Should Sneakers Fit?


Close up of young woman getting ready for jogging outdoors while lacing her pink sneakers

You’d think it would be easy to know when a pair of shoes fits perfectly, but it’s not always so straightforward. Sizing  is important for all types of footwear. However, it’s particularly crucial for all types of sneakers, as they’re made for continuous movement.

So, how should a sneaker fit? The footwear pros at Vionic are here to answer this sneaker industry question and provide helpful guidance on determining the proper fit for different types of trainers and walking shoes for women and men.

How Are Sneakers Supposed to Fit?

Ill-fitting shoes can cause a broad range of foot problems beyond just blisters, bunions, ingrown toenails, and general foot pain and discomfort. The wrong size can result in shin splints, alignment issues, and overpronation, which often leads to severe heel pain in the form of plantar fasciitis or Achilles tendonitis.

These foot conditions can be severely debilitating, sometimes preventing people from putting any weight on their feet. Needless to say, selecting shoes that are too long, wide, or narrow can result in serious foot woes.¹ Finding the perfect fit for tennis shoes isn’t rocket science, but there are a few things to keep in mind.

Properly fitting sneakers will:

  • Have footbeds that are between 0.5 to 0.65 inches longer than your foot
  • Fit snuggly but not too tight
  • Provide wiggle room for your toes
  • Not push into your toenails
  • Cup your heel comfortably
  • Not slip around your heel or any other areas of your foot
  • Be broad enough to accommodate the width of your foot without excess space

Most sneakers are intended to be worn with socks, especially active styles like the running sneaker. For this reason, make sure you always try on trainers while wearing socks. The same goes for casual sneakers, unless they’re meant to be worn barefoot. Also, keep in mind that not all socks are created equal. If you plan to wear a pair with thick athletic socks, try them on with dress, sheer, or otherwise thin socks won’t cut it.

Additionally, if you wear orthotic insoles with your sneakers, be sure to put them in before trying them on. Inserts can be placed over the footbeds or in place of the existing insoles.

The Finger Test

You slip into a pair of athletic shoes, and they feel good on your feet—not too loose, not too tight.² But how do you know if they’re the right fit? The finger test can help find the right size.

While wearing the shoes, place one finger between your heel and the heel counter (back of the running sneaker). Ideally, it will slide in easily but feel relatively snug. If you can’t get your index finger in or have to force it, the sneakers are probably too small. If you can effortlessly fit two or three fingers behind your heel, they’re too large.


How Are Running Shoes Supposed to Fit?

Running is one of the purest and most popular forms of exercise. Apart from getting the right gear, it doesn’t cost any money. And, weather permitting, you can do it anywhere, anytime.

Having said that, every runner needs not only proper footwear but also properly fitting footwear. How are running shoes supposed to fit? Following the sneaker fit guidelines, we outlined above is a great place to start, but we’ve got a few more pointers for determining the right size.

Don’t Overlook Wiggle Room

When it comes to running shoes, wiggle room is of the essence. When you hit the trails or pound the pavement, your toes endure substantial impact with every stride.³ Without any space to move, they can’t effectively absorb this impact. This can wreak havoc on your feet, ankles, calves, and hips.

As we mentioned, most shoes should be between 0.5 to 0.65 inches longer than your feet, but runners may want to err more toward 0.65 inches of additional space. The finger test can tell you whether you have enough wiggle room. If you can’t fit your index finger behind your heel, the running sneakers are definitely too tight.

The Rule of Thumb

Another trick for knowing whether sneakers fit properly is to press your thumb down on the front of the shoe, right at the tip of your longest toe. When standing or crouching, there should be between 0.35 and 0.5 inches of space between your longest toe and the front of the athletic shoe (or about the width of your thumb).

This is where the idea of wiggle room comes in. The toe boxes should provide you with plenty of room to move your toes while standing up in running shoes.

Should You Go Up a Size?

Running shoes that are too large can cause foot problems, but tight-fitting sneakers are a common mistake. To avoid the issue, many runners opt for a half-size larger than they normally wear.⁴

This ensures there’s plenty of wiggle room for the toes, allowing your feet to properly absorb impact. And since the difference of one half-size is usually only between 0.13 to 0.25 inches, the risk of getting running shoes that are too large is low.

With that said, this really depends on the brand. If you’re browsing running shoes from a brand you’re familiar with, sizing up may be a good idea. On the other hand, if you’re considering shoes from a new company, you may want to try them on in a shoe store first. Otherwise, you can measure your feet carefully and compare your measurements against the brand’s size chart.

How to Measure Your Shoe Size for Sneakers

Measuring your feet to determine shoe size and the proper shoe fit is easy. We recommend checking both the length and width every couple of years or so, as your feet can expand throughout adulthood.

Follow these steps to measure your feet:

  1. Put on a pair of thick socks and stand on a piece of paper.
  2. Use a pen to draw the outline of both feet, pointing straight down toward the paper.
  3. Grab a ruler or tape measure and measure the longest and widest portions of each foot. (The longest portion is the distance from the outer tip of your longest toe to the back of your heel, and the widest portion is the broadest part of your forefoot.)
  4. Record your measurements and keep them on hand when reviewing fit guides.

Most people have one foot that’s ever so slightly longer than the other. You should choose your sneaker size based on your larger foot, as this will provide the most comfortable fit on both sides.

Casual and Active Sneakers from Vionic

Are you ready to gear up for your next workout or slip into a pair of wear-anywhere shoes? Vionic carries an impressive selection of casual and active sneakers for women and men. Each pair is designed with our exclusive Vio-Motion Support technology, ensuring orthotic arch support, plush cushioning, and heel stability are built into the soles.

When you slide into our fashion sneakers, walking shoes, cross-training shoes, or performance trainers, you’ll feel the difference right away. If you need help finding the perfect fit, we’re always here to assist.

We’ve got sturdy yet breathable athletic styles made for movement, as well as laid-back streetwear designs for kicking back and living life. We carry whole and half sizes for all sneakers, and many of our women’s athletic shoe styles come in wide widths. All of the sneakers you’ll find from Vionic prioritize both comfort and fashion, so you can look as good as you feel, no matter what you’re doing or where you’re headed.

Shop our comfortable sneaker collections today!


1. Terence Vanderheiden. “How to Find Shoes That Fit Your Toes”. Verywell Health. Updated on Aug 05, 2021,
2. Katy Hebebrand. “How to Choose the Best Running Shoes”. WebMD.
3. Sara Lindberg. “How a Running Shoe Should Fit. A Step-by-Step Guide to Finding the Right Shoe”. Healthline. Sept 1, 2020,
4. Cindy Kuzma. “Everything You Need to Know About Running-Shoe Size”. Runners World.
Jul 22, 2020,

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