Many novice runners assume that their shoe size for streetwear applies to their running shoe. This may be true for some, but it will also result in suboptimal trainers for countless runners.
I have found that your running shoes need to be slightly larger than your street shoes. Your feet will swell during exertion, making your “normal” sneakers too tight and restrictive during an intense training session.
The following breakdown looks at how I coach runners through arriving at their perfect fit.
The Steps for Measuring Shoe Size for Runners
Finding the ideal running shoe requires a combination of measuring and converting. To help you through the process, have the following materials handy:
- Paper – try to find a piece longer than the standard notebook size, as this will not be big enough for people with large feet. You can tape pieces together, but this can be a bit cumbersome. It is also more difficult to trace over tape. Poster board is ideal, as it provides a large surface area that will not buckle under pressure from your foot.
- Highlighter – many people use a pencil, which is fine, but I have found a highlighter to be much better. It makes a more discernible mark when lightly tracing.
- Cloth tape measure – this will be necessary for wrapping around the foot to measure width.
Now that you have the tools, it’s time to find the perfect fit!
Step One: Trace Your Feet
Yes, you read that correctly: trace both feet, not just a single foot.
Your feet are not the exact same size. If you only measure one and happen to choose the slightly smaller foot, you will end up with a pair of shoes that are too tight. If you measure and determine that there is a slight discrepancy, always choose your shoe size based on the slightly larger foot.
It is also important to remember to wear running socks when tracing your feet. Even the smallest fraction of an inch can mean the difference between sizing up or sizing down. As such, you want to most accurately reflect your feet in action when taking your measurements. So sock up!
On a similar note, it is also important to trace your feet at the end of the day. As your feet swell after exertion, they will be slightly larger at day’s end than when you wake up. And you always want to err on the side of bigger when choosing a comfortable running shoe.
Now to the tracing. Place your piece of paper or poster board on a firm, flat surface. Step gently onto the material.
It is ideal to have a friend trace around the outline of your foot. However, it is more than doable if you are working alone. Just be sure that you have the flexibility to reach down to the paper and that you can accomplish the movement without causing the paper to slip.
Hold your highlighter perpendicular to the paper. Lightly trace around the foot, keeping your marking instrument snug against the sock. I personally find it helpful to start with the hardest area to reach for a more natural flow around the foot.
Repeat the process for the other foot when complete.
Step Two: Measure the Length
Measure from the longest part of the heel (the center of the heel arc) to the end of the longest toe. Remember to measure to the inside marks of your outline for the most accurate results.
As mentioned, if these measurements are not the same for both feet, choose the larger of the two. I always advise athletes to trace their feet and measure multiple times just to be on the safe side.
Step Three: Measure the Width
Many runners think that they can determine their foot width simply by measuring across the same outline used for measuring length.
This is not sufficient!
Doing this will yield a result under 4 inches—an unrealistically narrow measurement that will not show up on a size chart.
You must measure all the way around your foot to get an accurate width reading. This is why a cloth tape measure is essential.
Step on the tape measure and pull it taut against the bottom of your foot. Adjust it so that it is directly beneath the widest part of your foot at the bunion joint.
Ensure that you have full weight on your foot for the most accurate measurement. Wrap the tape measure around your foot until it meets its end. You will likely get a measurement between 9 and 13 inches for men and 8 and 11 inches for women.
Step Four: Reference a Size Chart
A size chart will ultimately determine the size of running shoe you need.
The length of your foot will determine the numerical value of your shoe size. The width will determine whether you need a wide or regular model.
Remember that you want your running shoe to be slightly larger than your street shoe to accommodate for swelling during exercise. Therefore, it is best to start with a size .5 larger than what you would typically select for daily use.
Step Five: Try Out the Shoe
Select a pair of running shoes based on the size recommended from the chart. Try them on and use the index finger test to see how they fit:
- If your index finger slides down the heel of your shoe with ease, the shoe is too big
- If your index finger can enter the heel of your shoe with difficulty, it is a good fit
- If your index finger cannot fit into the heel of your shoe, the shoe is too small
If the index finger test reveals a good fit, give it a little more testing before making a purchase and hitting the trail. Jog lightly around the room. The shoe should remain in place without any rubbing against the heel.
If all of these boxes check out, you have officially measured for and selected the perfect running shoe fit!
FAQs – Frequent Asked Questions
How to Tell If My Running Shoes Are the Wrong Size
Even though you have measured for the correct shoe size, what started as the perfect fit on day one may no longer apply weeks into your running journey. The following are some conditions that can cause your running shoe needs to change:
- Growing feet – this is obviously a prevalent concern for teens and young adults, many of whom seem to change shoe size each week. However, growing feet are not completely uncommon for adults. Our feet tend to get wider and flatter as we age and the plantar fascia tendon stretches.
- Shrinking shoes – moisture causes most running shoes to shrink. This may come as the result of running in the rain or simply from the sweat given off during a run. As a result, it is best to choose waterproof running shoes to prevent this shrinkage as much as possible.
- Foot alterations and accessories – if along your running journey you start wearing special socks, using inserts, or require your ankles to be taped, it will likely result in the need for a different shoe size.
If you find yourself in a situation where you are no longer sure if your perfect fit still applies, look for the following signs that your shoes may be the wrong size:
- You have to completely unlace your shoes in order to get them off
- You can feel your toe grazing the front of your shoe toward the end of a run
- You notice bruising on your toenails
- Your feet and/or Achilles tendon are sore after a run
- You notice any kind of new pain in your lower extremities during a run
Do All Running Shoes Use the Same Measurements?
Unfortunately, the concept of a universal shoe size is not a reality for runners.
Different brands of running shoes are designed differently. Some will leave more room in the heel to accommodate for extra cushion. Others may utilize a unique lacing system that cause them to fit tighter than other brands.
In addition, many brands will have three categories of running shoe: neutral, stability, or motion control. Each of these are designed with specific performance in mind. Each will fit slightly differently.
The good news is that major manufacturers will provide their own sizing chart to help you arrive at the correct fit for each of their products. You can still use the measurements obtained in steps 1 through 3 listed above—just be aware that your shoe size may vary between brands based on their specific sizing charts.
What Happens If I Get the Wrong Size Running Shoe?
The effects of a poorly fitting running shoe are numerous.
In a best-case scenario, you will see slightly subpar performance on the track. Uncomfortable shoes may leave you thinking about your discomfort instead of powering through to your goal. For example, shoes that are too tight may cut off circulation to your feet, creating a distracting numbness. Shoes that are too big may leave you feeling like you are lugging around unnecessary cargo.
In a worst-case scenario, ill-fitting shoes will result in injury that keeps you off the trail.
Blisters can be extremely difficult to heal in the foot, as even day-to-day walking poses a threat to worsen the condition.
Moreover, poor-fitting shoes can cause you to change your gait, opening the door for serious injury. Sprained ankles and knees may arise from missteps. Overuse injuries such as plantar fasciitis, Achilles tendonitis, bunions, hammer toe, stress fractures, or corns will more easily arise as a result of an altered gait.
Measuring shoe size for runners involves taking the measurements of your foot and identifying the correct shoe size on a size chart. A few reminders about this process:
- Foot width requires you to measure around the widest part of your foot, not just measure the width of your traced foot outline
- Different brands and styles will have different sizing specifications, so be sure to refer to the specific size chart for most accurate results
- Running shoes usually need to be .5 size larger than street shoes
- Shoe size needs can change after use
Now that you know all of the important details for measuring for the correct running shoe size, go find your perfect fit and start running today!