adidas / February 2023

The Only Ultraboost Sizing Guide You’ll Ever Need

Upgrade your runs with the all new adidas Ultraboost Light. Read our size guide to discover the differences between the different shoes in the Ultraboost line.

So What Size Ultraboost Should You Get?

The answer depends on what you’re doing with your shoe. Looking for comfortable streetwear or a workhorse for marathon training? The difference matters, so here are a few tips to figure it out:
  1. Work out your true shoe size. Use our guide to get a precise measurement.
  2. Measure in the evening because feet tend to swell after being put to work all day.
  3. In between sizes? You might go one size down for a tight fit, or one size up to go loose.
With every release in the Ultraboost line, each feature is tuned for optimal fit, response, and performance during runs of all distances—from 1Ks to marathons. Let’s see how Ultraboost sizing breaks down for each version.

Ultraboost Light: Epic Energy. Lightest Ever

Ultraboost Light is the lightest Ultraboost shoe to date. It is a neutral running shoe offering the ultimate cushioned & responsive experience. Its heightened level of comfort & style means the shoe has a versatility that can take its use case beyond the run.

How It Fits For Men

With the new and improved pattern fine tune the Ultraboost Light shoe makes choosing your size easy. With the lower tongue top and collar line of the shoe, this has improved the way the shoe fits your foot.
An innovative pattern spring adjustment for this latest iteration of the shoe makes stepping into the shoe light work. This, combined with the smaller and thinner tongue top logo has maximized the step-in stretch when putting on your shoe before you head out on your run. The newly optimized KNIT stretch along collar line also allows for an easier step in fit.
The last feature of the shoe to talk about is the minimized quarter reinforcement, again optimizing the midfoot adaptive stretch. These features combine for a shoe that not only moves as you do, but also allows you to easily pick your size without worrying about a shoe that won’t fit your foot.

How It Fits For Women:

The new last, born from the foundations of the signature S-curve UB21 last, was fine-tuned to create a narrower heel pocket, shallower forefoot profile and lower instep area to optimize fit for the female foot.

How To Pick Your Size

The Ultraboost Light Unisex & Ultraboost Light Wmn both fit true to size, so most people will be happy with their measured size.

Ultraboost 21 Sizing: Innovation After Innovation

In hot pursuit of the ultimate running experience, Ultraboost 21 is designed to harmonize three key factors in running footwear: weight, cushioning, and responsiveness. With 6% more Boost capsules in the midsole than Ultraboost 20, these shoes are built to maximize energy return each time your foot hits the ground.

How it fits:

The Primeknit+ FORGED upper is optimized for stretch only where you need it, while also providing allover support. Internal heel pillows in the midsole are strategically placed to prevent your foot from slipping—enhancing the secure, sock-like fit of Ultraboost 21.
How to pick your size: Like previous iterations, Ultraboost 21 is designed to fit true to size.

Ultraboost 20 Sizing: Say Goodbye To Gravity With the Ultraboost 20

Like its predecessor, Ultraboost 20 features a midsole with 20% more Boost capsules than previous versions, fine-tuned torsion system, and a coreless 3D heel frame—plus some new features, like precisely-placed Tailored Fiber Placement (TFP) stitching in strategic areas of the Primeknit uppers.

How it fits:

The shoe features Primeknit with TFP stitching to provide an optimal balance of sock-like fit and support exactly where you need it in every stride. In addition, a new heel construction provides enhanced padding around the Achilles for an improved heel fit. Combined with the iconic Boost midsole and Torsion system from the Ultraboost 19, Ultraboost 20 will help you chase your personal best on every run. 

How to pick your size:

Ultraboost 20 sizing is true to size. If you have wide feet go a half size up.

Ultraboost 19 Sizing: Rethought.Recoded.Reboosted.

Ultraboost 19 takes an innovative approach to running footwear by focusing on four key features: seamless fabric, improved energy return, fine-tuned torsion, and re-engineered heel support. “We went back to the drawing board for Ultraboost 19,” explained Sam Forester, the Director of Development for performance running footwear. “It was challenging, but we knew that runners around the world would be better off for it.”

How it fits:

The shoe features Primeknit 360—a seamless 3D knit upper woven to offer a fit so close it’s hard to feel where your foot stops and the shoe starts. But the tech benefits don’t stop there—the coreless 3D heel frame keeps your foot firmly in place during even the most strenuous workout.

How to pick your size:

Ultraboost 19 sizing is true to size, and the precision fit of the 3D knit upper means just about anyone will feel right at home wearing their measured size.

Ultraboost: From Running To Streetwear

While all Ultraboost shoes deliver style, support, and the ultimate cushion, this iconic shoe has evolved to meet modern runners where they are today. Ultraboost 19 to the Ultraboost Light are made with performance features designed and tested for a superior running experience. Other models of the Ultraboost are rooted in running but have been adopted by streetwear enthusiasts, creating a comfortable, casual aesthetic that is versatile for everyday wear.

Ultraboost 4.0 Sizing: Improving On Greatness

Adaptive, comfortable, energizing. Through painstaking attention to detail and constant collaboration with users, the 4.0 built on every release before it to become the one running shoe to rule the road.

How it fits:

The 4.0 brought back the extra-breathable mesh from early Ultraboost models and evolved the heel counter to give the Achilles even better support. Set atop the stretchweb outsole, it delivered on comfort, traction, and energy feedback for lengthy runs.
How to pick your size: Wider-footed runners should go a half size up. Those with normal or narrower feet should stick with a true-to-size fit.

Ultraboost 3.0 Sizing: Expanded colors, Expanded Fit

The 3.0 blew up the style potential of the Ultraboost with a surge of midsole color options. Sneaker collectors went wild, and besotted run crews from cities around the world helped the shoe make an indelible mark on the running landscape.

How it fits:

This was the first Ultraboost with an entire upper constructed of Primeknit. With the 3.0, the Ultraboost went from feeling like a sock to something approaching a second skin, thanks to motion weave technology enhancing the overall stretchiness of the upper.

How to pick your size:

With an even more flexible construction, the 3.0 should be a true-to-size fit for just about everyone.

Ultraboost 2.0 Sizing: The Greatest Ever, Again

The second Ultraboost drop was the continuation of a running juggernaut, incorporating user input to significantly up the comfort factor of the upper.

How it fits:

Subtle updates to the weave improved how the upper hugged your foot, while the same Primeknit comfort and breathable mesh that made the 1.0 (OG) such a solid shoe allowed you to run without any discomfort.

>How to pick your size:

Ultraboost 2.0 is similar to the 1.0 (OG), so go with your regular size, unless you have wide feet. In that case, go a half size up.

Ultraboost 1.0 (OG) Sizing: A Game-Changing, High Performance Fit

In 2015, the first Ultraboost bridged the gap between form and function with a silhouette that caught the attention of world-class runners, force-of-nature celebs, and sneakerheads alike.

How it fits:

“While we mostly got attention from users for the midsole, during development the fit was our quiet obsession,” said Forester. That fit was achieved through the sock-like comfort of the Primeknit-laden upper and the highly breathable perforated mesh of the tongue. 

How to pick your size:

Ultraboost 1.0 (OG) sizing is true to size, so for most people their measured size is the way to go. For wider feet, go a half size up. 

Ultraboost Uncaged Sizing: Refinde To The Essentials

The Uncaged was designed for minimalist runners who were cutting the cage off their Ultraboosts. But the Ultraboost team didn’t just cut away tech here. They reinforced the upper to ensure it could handle long stints on the road without the cage.

How it fits:

“Our top priority was a high-performance, supportive fit without a cage. To accomplish this, we had to internally reinforce the weave of the Primeknit upper,” explained Matthias Amm, the product category director for adidas global running. The result feels like an ultra-strong sock that fully supports the midfoot.

How to pick your size:

The Uncaged is true to size, so most people will be happy with their measured size. Go a half size up if you have wide feet.
adidas / February 2023