Buying sneakers online can be challenging when you're not sure what size to choose, especially when comparing major brands like adidas and New Balance. While shoe sizes follow universal measurements, subtle differences in length and width between brands can affect the way each pair fits.
To help you buy confidently, we've created this complete guide comparing adidas vs New Balance sizing. We’ll break down the fit differences, how both brands handle shoe width, and which models run wide or narrow.
So, if not knowing what size shoes you need is holding you back from buying new trainers from either adidas or New Balance, make sure you stick around as our guide has the answers.
How Should Sneakers Fit?
Before comparing sizes, it’s crucial to understand how sneakers should fit for optimal comfort and performance
Length:
According to Clarks, you should leave a finger-width of space between your longest toe and the tip of the shoe. This ensures enough room for natural movement and helps align the shoe's curve with the ball of your foot.
Width:
The widest part of your foot, usually the ball and metatarsal area, should sit within the widest part of the shoe. If your feet feel squeezed or your toes are pressed inward, the shoes may be too narrow. Too much space, on the other hand, can lead to slipping and a lack of support.
Unfortunately, determining the width of shoes is a little trickier. It's relatively uncommon for brands to give specific measurements for the width of their trainers. And while New Balance does have its own width chart, it doesn't necessarily help when it comes to figuring out whether or not you need wider or narrower shoes.
adidas vs New Balance Sizing: Comparison
When it comes to length, adidas and New Balance sizing is remarkably similar. For example:
- A Men’s US 9 in adidas translates to an EU 42 2/3.
- A Men’s US 9 in New Balance is equivalent to EU 42.5.

This tiny variation, less than a third of a size, is barely noticeable in practice. That means you can typically wear the same US size in both brands without issue.
Remember: Fit may vary depending on the specific model and design materials. If you're not sure, you can explore adidas and New Balance size charts here.
Which adidas and New Balance Shoes Fit Wide Feet?
One of the biggest differences between adidas and New Balance lies in how they address foot width.
adidas primarily features wide-fitting options in their running shoe line, with the Runfalcon 5 standing out among them. However, New Balance boasts a broader collection, inclusive of Wide, Extra Wide, and XX-Wide versions, such as the popular 990v6 model, making it a go-to for wider-footed individuals.

Which adidas and New Balance Shoes Run Narrow?
Certain models from both brands are known to fit on the narrower side, especially performance running shoes built with lightweight materials.
Running shoes, in particular, often fall into this category. The adidas Ultraboosts, for example, can sometimes feel like they fit tighter than some of adidas' other great footwear due to their PRIMEKNIT uppers.

The same also applies to some of New Balance's sportswear shoes. However, New Balance does offer one of the largest selection of shoe widths around, ranging from 2A X-Narrow to 6E XX-Wide, with the aim of having a pair of sneakers to suit every foot type available.
Final Thoughts
Both brands offer high-quality footwear, but they serve different sizing needs:
- If you have wide feet or need extra sizing flexibility, New Balance is the better option.
- If you're looking for a snug, athletic fit, especially for running or training, adidas may be a great choice.
Before buying, always consult the brand’s official size chart, try on different styles if possible, and check return policies in case the fit isn’t perfect on the first try.