Yeezy Boost Explained: Comfort, Sizing, and What to Know Before Buying

Quick answer: Yeezy Boost sneakers feel so comfortable because of adidas Boost foam. Boost is made of thousands of small foam beads fused together, so it feels soft but springs back with every step, and it doesn't go flat as fast as many standard foams. Fit depends on the model: the Yeezy Boost 350 V2 runs small, so most people go up a half size, while the Yeezy Boost 700 fits close to true to size. adidas ended its Yeezy partnership in 2022, so today most Yeezys are bought and sold on the resale market. If you just want Boost comfort, adidas still uses Boost foam in shoes like the Ultraboost.

Boost is adidas' name for a foam made from expanded TPU (thermoplastic polyurethane), developed with the chemical company BASF. It starts as tiny plastic pellets. Steam puffs them up into small foam beads, and the beads are fused together into a midsole. That bumpy "popcorn" look on the side of the sole is the Boost.

Each bead works like a tiny spring. When you step down, the beads squish. When you lift your foot, they bounce back. That's why Yeezy Boost models like the 350 V2 and 700 feel soft without feeling mushy, and why so many people wore them for long days on their feet.

Boost is very soft, so a common question is whether the shoe feels stable.

JD Expert Question: Does the soft Boost sole on the Yeezy 350 V2 give enough support for all-day walking, and how does it hold up over time?

JD Expert Answer: For everyday wear, yes. The ribbed rubber cage around the Boost keeps the foam from spreading out to the sides, so your foot stays centered. The 350 V2 doesn't have a stiff arch plate, so it feels flexible and relaxed rather than locked in. If you need real arch support, or you plan to run or train, choose a running or training shoe instead. Boost keeps its bounce well, but the rubber outsole still wears down, so check the tread on older or resale pairs.

• Comfort over time:

• Yeezy Boost: Keeps its bounce for a long time.

• Standard EVA: Can pack down and feel flat after lots of wear.

• Cold weather:

• Yeezy Boost: Stays soft when it's cold out.

• Standard EVA: Can feel stiff in cold weather.

Yeezy fit changes a lot from model to model. Here's the short version, based on fit feedback from JD store teams:

• Yeezy Boost 350 V2: Runs small and a bit narrow. Most people go up a half size. If you have wide feet, think about a full size up.
• Yeezy Boost 700: Fits close to true to size. The padded upper feels roomy enough for most feet.
• Yeezy 500: Close to true to size with a roomy toe box. Some people with narrow feet go down a half size.
• Compared to Nike and other adidas: Start with the size you wear in most Nike and adidas sneakers. Use that size for the 700, and go up a half size for the 350 V2.

• 2015: The Yeezy Boost 750 and then the Yeezy Boost 350 launched as part of the adidas partnership.
• 2016: The Yeezy Boost 350 V2 arrived with its see-through side stripe and became the line's best-known shoe.
• 2017: The Yeezy Boost 700 "Wave Runner" helped kick off the chunky sneaker trend.
• 2022: adidas ended the partnership. It later sold off the remaining pairs, and no new Yeezy Boost models are being made.
• Today: Yeezys are mostly bought and sold on the resale market. If you buy resale, make sure the pair is authentic and check the condition of the sole.

• Why are Yeezys so comfortable? Most Yeezy Boost models use a full-length Boost midsole, which feels soft and springs back with each step.
• Do Yeezy 350 V2s run small? Yes. Most people go up a half size. Wide feet may need a full size up.
• Is Boost good for walking all day? Yes. Boost is soft and keeps its bounce, which is why many people wear Yeezys for long days on their feet.
• Are Yeezys still being made? No. adidas ended the partnership in 2022, so new Yeezy releases have stopped. Pairs now sell mainly through resale.
• What shoes feel like Yeezy Boost? Look for adidas sneakers with Boost cushioning, such as the Ultraboost.

Who should wear Yeezy Boost?

Yeezy Boost is for anyone who wants a soft, easy, all-day sneaker with a look people recognize right away. The 350 V2 is the classic pick if you don't mind sizing up. The 700 is the better pick if you want a roomier fit and a chunkier style.

• Ready to shop? Yeezys are no longer being released, so check what's available before you buy. For the same kind of Boost comfort, browse adidas sneakers at JD Sports.

• adidas Product Information: Details on Boost cushioning, Primeknit uppers, and the Yeezy Boost models.
• Materials Background: General information on expanded TPU foam and how it compares with EVA foam.
• Brand History: Public reporting on the adidas Yeezy partnership from 2015 to 2022.
• JD Sports Fit Feedback: Sizing and comfort feedback from JD Sports store teams across North America.