adidas Ultraboost 2.0 fits true to size for most people — the same number as Air Jordan 1, Air Max 90, Vans Authentic, and YEEZY Boost 350 V2, and about half a size larger in number than your Air Force 1. The Primeknit upper hugs the foot and the Boost midsole compresses slightly with wear. Based on 451 owner-reported pairs in the Feetlot database, the typical wearer takes the same number in Ultraboost 2.0 as in any other Ultraboost generation. If unsure: order true to size. Wide feet should size up half — the Primeknit accommodates some width but the heel cage doesn't.
Ultraboost 2.0 Sizing — What 451 Pairs in the Feetlot Database Tell Us
The adidas Ultraboost 2.0 is among the most-tracked Ultraboost generations in the Feetlot database alongside the 4.0. Across 451 owner-reported pairs, the residual variance is tight (standard deviation ≈ 0.24 size units), meaning sizing is consistent across the various UB 2.0 colorways (Triple White, Core Black, Parley). Feetlot data confirms what sneaker retailers say: Ultraboost 2.0 fits true to size — the same number as Air Jordan 1, Air Max 90, and Vans Authentic, and about half a size larger in number than AF1.
The reason Ultraboost 2.0 fits true to size is the Primeknit-and-cage construction. The Primeknit upper sits closer to the foot than AF1's padded leather, and the molded heel counter plus the Torsion bar hold the foot at length. The Boost foam compresses by 1–2 mm at the heel after the first 10 hours of wear but doesn't change length. Going below true size pinches the toes against the rigid heel cage.
Should You Size Up or Down in Ultraboost 2.0?
Standard fit (most people)
Order true to size — your usual sneaker number (same as AJ1, AM90, SB Dunk Low, Vans Authentic). Don't apply the "half down from AF1" adjustment here — Ultraboost 2.0's snugger construction doesn't leave AF1's heel slack, so bringing your AF1 adjustment gives a too-short shoe.
Wide feet
Size up half. The Primeknit upper accommodates moderate forefoot width, but the heel cage and midfoot Torsion bar limit how much stretch is useful. Width isn't offered separately on most UB 2.0 colorways. Half a size up is the standard wide-foot adjustment in the Feetlot database.
Narrow feet
True to size works for most narrow feet — the Primeknit wraps the foot at true length. Going half down can fit very narrow feet but risks heel slippage inside the cage.
Ultraboost 2.0 vs Ultraboost 1.0, 3.0, 4.0
All four original Ultraboost generations (1.0 through 4.0) fit within a quarter size of each other — same size advice across all of them. The differences are in midsole density, upper knit construction, and the heel counter geometry; the length you'd buy is the same. If you own a UB 4.0 in your true size, take the same number in UB 2.0.
How Ultraboost 2.0 Compares to Other Sneakers
The adidas Ultraboost 2.0 fits at the same numerical size as Air Jordan 1, Air Jordan 3, Air Jordan 4, Air Jordan 5, Air Jordan 11, Nike Air Max 90, Nike Air Max 1, Air Max 95, Air Max 97, Air Max 270, Nike Dunk Low, Nike Dunk High, SB Dunk Low, Nike Blazer Mid '77, Vans Authentic, Vans Old Skool, adidas Gazelle, adidas NMD R1, adidas YEEZY Boost 350 V2, and New Balance 574. According to Feetlot data, all of these round to the same size in 0.5 increments — same number you wear in Ultraboost 2.0.
The shoes that run larger in number than Ultraboost 2.0: Nike Air Force 1 runs about half a size smaller in number — if you wear AF1 in 10, take UB 2.0 in 10.5. Converse Chuck Taylor Ox, Converse Chuck Taylor Hi, adidas Superstar, adidas Stan Smith, and Sperry Authentic Original also run about half a size smaller than UB 2.0 in number.
Boot-style models: Clarks Desert Boot and Red Wing Iron Ranger run about a full size smaller in number than Ultraboost 2.0 — if you wear UB 2.0 in 10, take Desert Boot or Iron Ranger in 9.
Sign in to Feetlot and add a few of your other sneakers to get a personal Ultraboost 2.0 size recommendation calibrated to your actual foot.
adidas Ultraboost 2.0 Size Chart (US / EU / UK)
| US Men's | US Women's | UK | EU |
|---|---|---|---|
| 7 | 8 | 6.5 | 40 |
| 7.5 | 8.5 | 7 | 40.5 |
| 8 | 9 | 7.5 | 41.5 |
| 8.5 | 9.5 | 8 | 42 |
| 9 | 10 | 8.5 | 43 |
| 9.5 | 10.5 | 9 | 43.5 |
| 10 | 11 | 9.5 | 44 |
| 10.5 | 11.5 | 10 | 44.5 |
| 11 | 12 | 10.5 | 45.5 |
| 11.5 | 12.5 | 11 | 46 |
| 12 | 13 | 11.5 | 47 |
| 13 | 14 | 12.5 | 48 |
Common Sizing Mistakes
- Buying UB 2.0 in your AF1 size. AF1 runs about half a size smaller in number than Ultraboost 2.0. If you wear AF1 in 10, take UB 2.0 in 10.5.
- Sizing up because "Ultraboost runs small." Ultraboost 2.0 runs at true Nike sneaker size, which feels large compared to AF1 (which already runs roomy). True-to-size is correct; don't add an extra half up on top.
- Expecting the heel cage to soften. The plastic heel counter doesn't flex meaningfully with wear. If true-to-size feels tight at the heel, the geometry isn't a fit for your foot; the Ultraboost 21/22's redesigned cage may help.
- Bringing your Chuck Taylor or Superstar size over directly. Both of those run about half a size smaller in number than UB 2.0. If you wear Chuck Ox in 10, take UB 2.0 in 10.5.
- Confusing UB 2.0 and UB 4.0 sizing. They're the same — all Ultraboost generations (1.0–4.0) round to the same size. No adjustment needed between generations.
How Feetlot Computes These Numbers
Every Ultraboost 2.0 sizing recommendation on Feetlot is the output of a global offset model fit to over 100,000 owner-reported shoe records. Each shoe gets a single number — its "size offset" — that captures how its sizing drifts relative to a reference shoe (the Nike Air Force 1). When a Feetlot user provides their size in any tracked shoe, the model recovers their true foot baseline and recommends the matching Ultraboost 2.0 size.
This works better than the pairwise approach you'll see on most sizing blogs because Feetlot uses the entire wardrobe graph. A YEEZY 350 owner contributes data about how YEEZY fits relative to AF1 owners (who often own both), which links back to Ultraboost 2.0 owners through any shared model. Even when two users share zero shoes directly, the chain of users in between transmits a consistent recommendation. The result: sizing advice that holds up no matter how unusual a wardrobe is.