As a running coach, one of the most popular questions I get asked by my athletes is which running shoes they should buy and how they should fit.
It may seem obvious, but your running shoes must fit your feet properly and feel comfy from the very first time you try them on.
A good fit can mean the difference between a comfortable, injury-free run and one that leaves you wincing with every step.
But how exactly should running shoes fit? Loose, tight, somewhere in the middle?
In this guide, I’ll walk you through the essentials of finding that perfect fit covering everything from the toe box to shoe width and heel snugness, and explain why each detail matters.
So, get ready to find the right running shoes for you—your feet will thank you!
The Importance of Measuring Your Feet for Running Shoes
Many runners think that they know their shoe size, particularly in terms of length, but the size and shape of our feet change over time.
In fact, a review in the Journal of Foot and Ankle Research1Buldt, A. K., & Menz, H. B. (2018). Incorrectly fitted footwear, foot pain and foot disorders: a systematic search and narrative review of the literature. Journal of Foot and Ankle Research, 11(1). https://doi.org/10.1186/s13047-018-0284-z found that up to 72% of individuals are actually wearing shoes that do not fit their feet properly.
Pregnancy,2Wetz, H. H., Hentschel, J., Drerup, B., Kiesel, L., Osada, N., & Veltmann, U. (2006). [Changes in shape and size of the foot during pregnancy]. Der Orthopade, 35(11), 1124, 1126–1130. https://doi.org/10.1007/s00132-006-1011-1 changes in weight, aging, and even tons of running itself can potentially widen and lengthen your feet over time.
Accordingly, measuring your feet at least once a year, if not every six months, is best. If you have experienced significant weight changes or have had a pregnancy, you should measure your feet before buying your next pair of running shoes, as your foot size may vary.
The actual size of the running shoe that you need should be determined after properly measuring your foot.
You can measure your foot at home and then compare your measurements to the shoe size chart of the brand you want to buy. Alternatively, you can go to your local specialty running shop or athletic footwear store and get measured by a professional.
One important thing to note is that you need to trace and measure both feet. Many people have one foot that is longer and/or wider than the other. When buying running shoes, you need to use the size corresponding to your larger foot.
Using different shoe lacing techniques, you can usually secure and snug the smaller foot in a slightly larger shoe necessary to accommodate the larger foot.
If you have doubts about the size you should go with after your measurements, particularly if you fall between two sizes in length or width, you should go with a half size up (some even a full size up) or the larger of the two sizes.
Another important thing to note is that it is best to measure your feet or go to the running store to get sized for your shoes in the afternoon or evening, particularly if you tend to run later in the day.
Our feet swell over the course of the day, so if you measure or get fitted in the morning and you are an evening runner, your running shoes may feel too snug.
It is also important to measure your feet wearing the socks you intend to run in. Some runners like wearing thicker socks with more cushioning and warmth, which can add appreciable width and length to their feet.
If you trace and measure your foot without socks and then choose to wear cushioned running socks, your running shoes will feel tight.
The same applies when you get measured or try running shoes at the store. Always wear or bring the running socks that you typically train in. This will help ensure you find shoes that will fit right once you have your socks on.
Some running stores may also offer gait analyses, in which you run on a treadmill and measure any pronation or supination to determine which shoe is best for your biomechanics.
How Should Running Shoes Fit?
Before we discuss the specifics of what to look for and how running shoes should fit, it’s important to note that the ultimate answer is that running shoes should fit comfortably.
This means that when you try on a pair of running shoes, they should feel comfortable right out of the box.
Some runners assume there should be a big “break-in period,“ in which the shoes stretch out or feel more comfortable after their initial snug fit.
While it is true that the shoes may begin to soften and feel a bit more comfortable after you’ve logged a decent number of miles, the pair of shoes should feel comfortable brand new.
If they feel too snug or stiff, it is not the right shoe or fit for you.
You can usually tell right away if a running shoe fits properly because your foot should feel comfortable and supported without being squeezed, yet the shoe should not be loose enough that you are swimming around in it.
With that said, here are some specific pointers for determining if your running shoes fit properly:
How Should The Upper Of A Running Shoe Fit?
The upper, which refers to the top part of the running shoe that surrounds your foot, should fit your foot well.
Bony parts of your anatomy should not stretch or feel like they are abutting against the inside mesh of the shoe.
What Is The Ideal Fit In The Toe Box Area?
The toe box is the front of the shoe where your toes and the ball of your foot reside.
There are two things to pay attention to with the fit of the running shoe in the toe box area. You should be able to wiggle your toes and feel like they can spread out flat without being compressed by the width of the shoe.
It should be wide enough to accommodate natural foot splay or the flattening and widening of the foot when you bear weight.
In terms of the length, you should have about a thumb’s width or half an inch between the length of your longest toe and the end of the shoe. If not, you are at risk of losing a toenail or two!
For trail running, you may even need a bit more space for steep downhill running.
If you don’t have enough wiggle room and your toes feel cramped either in terms of length or width, you should size up.
If you have bunions or wide feet, you should try shoes with a wider toe box for more comfort and extra room.
How Should The Midfoot Fit?
The midfoot of the shoe should be pretty snug so that you have decent arch support, but your foot should not feel compressed from side to side.
You can adjust the tension in the shoe laces along the midfoot to get a proper fit. This will prevent the shoe from pulling on your foot as you run or allowing your foot to slip up and down because the shoe is too loose.
Another important consideration with the set of the midfoot portion of the shoe is that your anatomical mediolateral arch should line up with the midsole arch of the shoe.
If the shoe’s arch support is not lined up with your own arch, it can cause pain and may alter the biomechanics of your foot during the transition from contact to toe-off.
How Does The Shoe Shape Affect The Fit?
Look at the overall shape of the shoe. The shoe last refers to the foundation on which the shoe is built, and each running shoe brand and type of shoe has a different shoe last shape.
Considering the shape of the shoe extends beyond just its overall width, some running shoes have a more squared-off forefoot region by the toes, whereas others taper more.
Look at your foot shape or tracing compared to the shape or tracing of the outsole of a running shoe, or, if possible, pull out the insole and compare it to your foot shape.
The insole shape will give you a much better idea of the shoe’s actual shape and fit. Many running shoes now build up the base, and they have a much wider platform than the actual shoe, particularly around the heel.
This can skew the comparison of your foot shape to the true shape of the inside of the shoe, which ultimately affects how the shoe fits your foot.
You want the shape of the shoe’s sole to match your own shape as closely as possible.
If you have a fairly rectangular shaped foot with a broader or wider toe box area, you want this to be reflected in the shape of the shoe. On the other hand, if your foot narrows out and tapers in your toe region, look for a running shoe shape that matches this pattern.
How Should The Heel Fit?
The ankle collar or heel cup around your foot should be nice and snug without squeezing your Achilles tendon.
You want there to be ample room to feel comfortable, but excessive width in the heel of the shoe will cause your heel to slip up and down as you run. This can cause blisters and irritation by constantly rubbing the back of your Achilles tendon.
What’s The Bottom Line?
If possible, test out several different brands, styles, models, and sizes of running shoes to ensure that you find running shoes that best fit your own foot shape and feel comfortable when you run.
Going to your local running store is a much better option than ordering running shoes online. You will most likely use a different size for your running shoes than your regular shoes, and sizes can even vary within brands depending on the model. Trying shoes on is a “must,” and the more variety you can try on, the better.
You know they are your shoes when you first slip them on, and they immediately feel comfortable.
Need a place to start? Check out our editor’s favorite picks:
