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Home » How Should Your Cross-Training Shoes Fit? Cross-Training Shoe Size Guide

How Should Your Cross-Training Shoes Fit? Cross-Training Shoe Size Guide

One of the most common questions I get asked on all of my cross-training shoe content is, “How does this model fit?” Sizing is quite possibly one of the toughest aspects to get right when shopping for new models. Plus, the last thing anyone wants to do is purchase a poor-fitting cross-training shoe.

As a cross-training shoe reviewer, it’s sometimes difficult to help others nail their sizing due to the sheer amount of differences that exist between all of our feet’ anatomy. For example, we have lifters with wider feet and others with high arches, all of these foot differences will influence how a shoe will fit.

To help you out, I wanted to put together a cross-training shoe sizing guide. This guide is intended to help suggest my sizing thoughts for a variety of cross-training shoes in 2021.

How Should Cross-Training Shoes Fit?

In general, you’ll want your cross-training shoes to have anywhere from .2″-.6″ of room at the end of your shoe’s toe box. This length is usually snug enough to prevent heel slip and not too tight to where your feet are cramping during workouts.

how should cross training shoes fit (1)

In addition to the above, when we consider cross-training workouts and the activities they include, we can better direct how we want our shoes to fit. For example, let’s say you’re primarily using your shoes to tackle plyometrics and HIIT workouts. This style of training will involve a lot of movements that have forward momentum.

If your shoes are too tight or too loose, then you can run into the issues of cramping and sliding around mid-workout. The last thing you want is your foot sliding around during something like a box jump.

In this context, a cross-training shoe that has around .4″ of room in the toe box would likely be a good option for a majority of athletes and lifters. Remember, when considering your ideal cross-training shoe size, consider how you actually train and what is most comfortable per your foot’s anatomy.

Cross-Training Shoe Sizing Guide

On my YouTube channel and on That Fit Friend, I always try to provide my sizing thoughts for the cross-training shoes that I review. If you’re interested in checking out how top shoes for certain categories compare to one another with sizing thoughts, then I’d highly suggest checking out my best cross-training shoe article and video.


Below, you’ll find every recent cross-training shoe that I’ve reviewed along with my sizing thoughts. For the record, I’m a size 10 with a “neutral” foot in regard to width.

Must Read: 8 Best CrossFit Shoes | Pick for Rope Climbs, Flat Feet, and More!

Reebok Cross-Training Shoe Size Guide

  • Reebok Nano 8: True-to-Size (wider width)
  • Reebok Nano 9: True-to-Size
  • Reebok Nano X: True-to-Size
  • Reebok Nano X1: True-to-Size
  • Reebok Nano X1 Froning: True-to-Size, but slightly long in the toe box.
  • Reebok Nano X1: Adventure: True-to-Size
  • Reebok Speed TR: True-to-Size, but more narrow last. Not a great option for wider feet.
  • Reebok Nanoflex TR: True-to-Size
  • Reebok Flashfilm Train 2.0: True-to-Size

Nike Cross-Training Shoe Size Guide

  • Nike Metcon 5: True-to-Size, but more narrow last. Not a great option for wider feet.
  • Nike Metcon 6: True-to-Size, but more narrow last. Not a great option for wider feet.
  • Nike Metcon 7: True-to-Size, but more narrow last. Not a great option for wider feet.
  • Nike Free Metcon 4: True-to-Size, but fits more narrow.
  • Nike React Metcon Turbo: True-to-Size.
  • Nike Renew Retalation TR 3: True-to-Size.

Under Armour Cross-Training Shoe Size Guide

  • UA TriBase Reign 2: True-to-Size, runs a tad more neutral.
  • UA TriBase Reign 3: True-to-Size, runs a tad more neutral.
  • UA HOVR Rise 2: True-to-Size
  • UA HOVR Rise 3: True-to-Size
  • UA HOVR Apex 3: True-to-Size
  • UA Project Rock 3: Runs small, size up .5-1 size.

Inov-8 Cross-Training Shoe Size Guide

  • Inov-8 F-Lite 235 V3: True-to-Size, but runs a bit more narrow.
  • Inov-8 F-Lite G 300: True-to-Size
  • Inov-8 F-Lite 245: True-to-Size
  • Inov-8 F-Lite 260 V2: True-to-Size, but the midfoot runs a bit narrow, so if you have wider or flatter midfoot, then you may want to explore other models.

On Cross-Training Shoe Size Guide

  • On Cloud X: True-to-Size

NOBULL Cross-Training Shoe Size Guide

  • NOBULL Trainers: True-to-Size
  • NOBULL High-Top Trainers: True-to-Size, but you may want to size up a half size if you generally feel cramped in your normal true-to-size models.

GORUCK Cross-Training Shoe Size Guide

  • GORUCK Ballistic Trainers: True-to-Size


  • STR/KE MVMNT Haze Trainer: True-to-Size
  • STR/KE MVMNT Vimana Run: True-to-Size

I Have a Wide Foot, Should I Size Up?

That depends. If you have a wider foot, then sizing up in certain models can lead to heel slip and actually hinder how a shoe fits you. When companies create cross-training shoes, they select a last (mold) that is, in theory, going to fit the grandest audience.

At times, the last a company selects to use may not align with your foot’s anatomy. A classic cross-training shoe example of this is how wider footed individuals often find Nike Metcons super uncomfortable, but enjoy shoes like Reebok Nanos.

In this example, the lasts that Nike and Reebok use are more narrow/neutral and slightly wider, respectively, which is why one might not align with your foot’s anatomy and the other does not. If you have a wider foot, then something like a Nike Metcon may never fit you perfectly.

Instead of sizing up, I’d suggest looking at other cross-training shoe options that have lasts that align with your foot’s anatomy better.

What Is Heel Slip?

Heel slip is a term used to describe what happens when the heel slips out of a shoe’s boot when exercising. Heel slip can occur when walking, jumping, lifting, and really during any movement that causes ankle dorsiflexion, AKA a movement pattern that can cause the heel to slip out of a shoe’s boot.

what is heel slip

Heel slip generally occurs when there’s excessive room in one’s shoe. If there’s too much room in the toe box, then heel slip can occur when the foot slides up during exercise. Conversely, if there’s too much room in the boot, then the heel can slip out during even the most casual movements like walking.

How Much Room Should I Have In the Toe Box?

A shoe’s tox box will vary with its width and what is ideal for you will depend on the anatomy of your foot. Wider toe boxes will accommodate greater toe splay. Toe splay is the act of spreading the toes out to increase the surface area of the foot to improve stability and balance when training.

For context, if you have a more narrow foot, then you can wear a wider variety of cross-training shoes. However, for my wider footed friends, you’ll be limited in which shoes fit best due to more narrow and neutral shoes feeling super tight in the toe box.

The ideal toe box will give you enough room to splay the toes when training, but not squeeze the lateral and medial toes too much. If you’re leaving training sessions with blisters on your pinky toe or big toe, then you likely should explore different shoes with wider toe boxes.

How to Measure Your Shoe Size At Home

If you’re interested in measuring your shoe size at home, there are a few simple ways to do so. To keep things simple, we’ll break this process into three steps.

Step 1: Grab a Piece of Paper, Pencil, and a Ruler

The first step is grabbing a piece of paper, a pencil, and a ruler. You’re then going to place your foot on the piece of paper and either 1) trace your foot, or 2) make a mark at the very end of the heel and your longest toe.

how to measure foot size at home

Step 2: Measure the Recorded Length

Once you’ve traced your foot or recorded its maximal points to determine its length, you’ll then measure your foot. You can also measure the width of your foot if you traced it to compare your foot’s width to some companies sizing charts if they provide a metric for establishing a shoe’s width.

With this measurement, you’ll then relate this measurement(s) to step 3 below.

Step 3: Compare Your Measurements With the Size Charts Below

Once you have your foot’s length, you’ll then compare it to the chart below to establish what size shoe you should be looking into. This can be really useful because some companies have their own sizing charts.

So, in the event a company has a more proprietary sizing system, then you can get a more accurate gauge for the shoe size that would fit your needs best.

Men’s Shoe Sizing Chart

For the men’s general shoe sizing chart in US and UK sizes, check out the graphic below.

men's cross-training shoe sizing guide

Women’s Shoe Sizing Chart

For the ladies, check out your sizing chart below for general US and UK shoe sizes.

womens shoe sizing guide

Outside of the above information, if you want the most accurate shoe size measurements, then I’d suggest visiting a shoe store where they can more accurately provide you with the dimensions of your foot.

In some cases, lifters, and athletes wear the wrong size shoes which can lead to models never feeling like they fit “perfect”. When in doubt, I’d suggest seeking out professionals in your area to go visit physically to get your most accurate foot measurements.

Takeaway Thoughts

In the vast cross-training shoe market, shoe sizing can be seriously confusing at times. With everyone’s anatomical differences, it’s impossible to create blanket statements that a shoe will fit everyone. This is why it’s important to acknowledge your individuality, then make shoe choices that actually align with your foot’s size.

If you have any questions on cross-training shoe sizing or need further assistance in regard to specific models, drop a comment below or reach out to me personally via Instagram (@jake_boly).


Jake Boly

I've been in the fitness and strength training industry for nearly a decade. In that time, I've trained hundreds of clients, written thousands of articles, reviewed over 100+ pairs of training shoes, and have produced a large list of training videos. I live and breathe fitness and training gear, and I think it's important that reviewers walk the walk with the gear they're testing. As for my educational background, I have my Masters in Sports Science, Bachelors in Exercise Science, and have my CSCS.

21 thoughts on “How Should Your Cross-Training Shoes Fit? Cross-Training Shoe Size Guide”

  1. Just got the Reebok X1 adventures and am stuck on the sizing. Ordered size 11 first which is my normal size and it just feels too loose. A lot of movement in my heels even when using the lace lock hole. So I got the 10.5 and they feel tight in the toes. Not able to spread out my toes very much without hitting the sides and the top of my toe is way closer to the front than usual in my other shoes. Not sure if this is something that will loosen up with time? Kind of stuck and unsure of which ones to keep and which ones to return.

    1. Hey, Hunter! This is a tough one because it may be that the Nano X1’s Adventure’s last doesn’t align with your foot’s anatomy a ton and that’s why it seems wicked difficult to find something consistent in regard to sizing that feels good/natural. IMO, the 10.5 may break in a loosen over time, but I’m also curious — do you have eyes on any other model, and what’s the intent behind the Adventure for you? If it’s for hybrid training/trail runs you could also check out the STR/KE MVMNT Vimana Hybrid Runner!

  2. Hello! I usually wear a size 6.5 women’s but my problem is that I have extremely narrow heels but need a normal width toe box. I feel that my left heel is substantially narrower than my right because my left heel positively SWIMS in my shoes while doing all the lateral movements of Zumba. I have a very high arch and severely under-pronate. I wear a Brooks Ghost, recommended by my physical therapist for the pain in my left ankle. The more I do Zumba, the more I feel that my ankle pain is due my left heel having what feels like a mile of wiggle room. I don’t feel that going to a narrow shoe would necessarily be the solution because the wide part of my foot fits fine. Sometimes I wear two socks on my left foot. I have tried the inserts and they don’t do anything, especially since I have to cut them in 2 to affect my heel width only and not the length. Do you have any suggestions? Thank you!

    1. You could try looking into a cross-trainer that has a slightly deeper boot and eyelets for lace-locking! That could help lock your heel down and give you a better fit which could translate to better performance and lower discomfort! If you need a few shoe suggestions lmk.

  3. Toe box space, What’s .2” to .6”? Is that decimal or 16ths, or what is it in metric? Sorry, never used inches and confused.

    1. No worries! Yes, that stands for inches. So, from inches to centimeters — .2″ = .508 centimeters to .6″ = 1.5 centimeters. Let me know if that answers your questions or if you need more help!

  4. My foot ended up measuring to be about 11 1/16″.
    So I would add .2″-.6″ to that to get my shoe size?

    I’ve been looking at buying the Haze Trainers, and with me having to buy them online I just want to make sure I’m getting it right 😅. I always find myself bouncing between 11 1/2’s or 12’s.

    1. Ah, what I’m referencing is check out your current shoe of choice and see how much room you have available. Once you’ve done that, assess if you like that much length in your toe box. When sizing new models, you’ll generally want to stay within that preferred range you currently have.

      I’d say go 12 for the Haze! I think that size would be perfect for you if you’re often between the two.

  5. Hey mate I’m currently running some old metcons (my pinky toe is splaying out over the sole) and whilst they do the job , I’m looking for something that is more suitable for my wide feet for my Crossfit training. I ran the same size in the nanos however I get heel slip.

    Don’t really care about asthetics or price just having a better fitting more comfortable (less muscle soreness in my arches) pair of training shoes.

    Any help would be appreciated thanks

    1. Hey! I would say look into the NOBULL Trainer+, STR/KE MVMNT Haze Trainer, or TYR CXT-1 Trainer when they drop in the fall. Those 3 should do better for you, but if none of those work — lmk and I can help you further!

  6. Hi Jake. I recently bought a pair of Reebok Nano X1’s on sale after the X2’s came out to use primarily for leg days and weight lifting at the gym. How tight do you want gym shoes to fit for that purpose? Do I want any extra room in the toes? This is my first pair of cross-training type shoes. I know with running shoes you want about 1/2″ extra to accommodate for foot expansion. According to my Fleet Feet analysis, my feet are on the wider side of normal width and measure right at a women’s US 10. I tried on Nano X1’s in both women’s 10.5 and 11. The 10.5 seemed like my toes touched the end of the shoe, mainly when I walked. So I went with size 11 and have about a thumb width of room at the toes and slight heel slip. Is this normal? Are these shoes too big for gym training? I’ve done a lot of research online with no definitive answer. Thank you!!!

    1. Hey Saidee! IMO, I feel like this model may not be the best for your foot anatomy based on your thoughts here. The 11 sound a little too big, as the main performance metrics that you’ll want to track when assessing size are 1) sliding around the toe box while training, and 2) heel slip. If you’re having a bit of both of those, I’d gather they’re too big.

      The 10.5 sound a little better, but even then, if your toes feel a bit too jammed in the toe box, then that could also be an issue. If they don’t bother you when training, I’d stick with the 10.5.

      With training shoes, it’s interesting because your training style/foot anatomy/fit preferences will all influence “how much” room you should have at the end of your toe box. The whole half inch logic doesn’t apply for most cross-training shoes as we all train differently with different intensities + styles, and we have to account for our individuality when it comes to anatomy. I always like using a range for this and suggest most lifters/athletes explore what typically feels best within said range so they’ll know what often works for them when purchasing future models!

      I hope that helps!

  7. Hello, I wanna get the Rad ones but I’m unsure if they will fit my feet given that I have wider feet (flat footed) . I had a size 9 with Metcon 6’s and had to remove the insole and replace it with an airforce one sole to fit my foot. Was rather happy with them after but they are worn out now so I wanted to try the Rad One’s. Also tried to find the right size but usure what the right one is.

    1. Heyo — hit you back in the other comment, but I’d pass on the RAD ONEs if you’re after more width/have flat feet. I think they’ll feel limiting even if you size up in them!

    1. Hey Kaleb! First off, thank you. Second off, not the best, honestly. If RAD would make a nice wide version…they would be OP, but as of right now, they’re not the best choice for lifters wanting more width!

  8. Hey, just wanted to say thanks for a helpful article! I am just starting out with lifting but realized my regular tennis shoes aren’t the best for doing so! This article helped me figure out a shoe that I believe will work best for me! I’m going to give the STR/KE MVMNT Haze Trainers a try due to my wider foot.

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