adidas Ultraboost 19 fits in the same number as Air Jordan 1, Air Max 90, Nike Dunk Low, and Nike Blazer Mid '77 — but about half a size smaller in number than Air Force 1 and adidas Superstar. At offset +0.281, Ultraboost 19 sits in the same zone as AJ1 (+0.217) and Dunk Low (+0.275), while AF1 (0.000) falls a half step below. Based on 134 owner-reported pairs in the Feetlot database: if your reference is AJ1 or AM90, order the same size. If your reference is AF1 or Superstar, size up half.
adidas Ultraboost 19 Sizing — What 134 Pairs in the Feetlot Database Tell Us
The adidas Ultraboost 19 is among the most-tracked Ultraboost models in the Feetlot database. Across 134 owner-reported pairs, the residual variance is tight (standard deviation ≈ 0.25 size units). At offset +0.281, Ultraboost 19 rounds to "same" as AJ1 (+0.217), AM90 (+0.314), Dunk Low (+0.275), Nike Blazer Mid '77 (+0.120), Forum Mid RS (+0.211), and adidas YEEZY Boost 350 V2 (+0.476) at 0.5 increments. AF1 (0.000) rounds to half a size smaller in number; adidas Superstar (−0.065) also rounds to half a size smaller in number than Ultraboost 19.
The Ultraboost 19's Primeknit stretch upper and Boost midsole create a snugger fit than the classic leather-cupsole baseline of AF1 and Superstar. This places UB19 solidly in the AJ1/AM90 half-step cluster rather than the AF1/Superstar cluster — a meaningful distinction when converting from adidas casual shoes.
Should You Size Up or Down in adidas Ultraboost 19?
Coming from AF1, adidas Superstar, or adidas Stan Smith
Size up half. AF1, Superstar, and Stan Smith run about half a size smaller in number than Ultraboost 19. If you wear AF1 in 10 or Superstar in 10, take Ultraboost 19 in 10.5.
Coming from AJ1, AM90, Nike Dunk Low, or Blazer Mid
Same size. AJ1, AM90, and Dunk Low all round to the same size as Ultraboost 19 in 0.5 increments. No adjustment needed.
Coming from adidas YEEZY Boost 350 V2
Same size. YEEZY 350 V2 (+0.476) rounds to the same size as Ultraboost 19 in 0.5 increments. Same number in both.
Coming from Clarks Desert Boot or Red Wing Iron Ranger
Size up. Heritage boots run smaller in number than Ultraboost 19 — size up half from Desert Boot, or a full size from Iron Ranger.
Wide feet
Size up half. The Primeknit upper of the Ultraboost 19 stretches but the last runs standard. Half a size up accommodates wider feet better than the standard D width.
How adidas Ultraboost 19 Compares to Other Sneakers
The adidas Ultraboost 19 fits at the same numerical size as Air Jordan 1, Air Jordan 4, Nike Air Max 90, Air Max 97, Nike Dunk Low, Nike Dunk High, Nike Blazer Mid '77, Vans Authentic, Vans Old Skool, adidas Forum Mid RS, Reebok Club C, and adidas YEEZY Boost 350 V2. According to Feetlot data, all of these round to the same size in 0.5 increments.
The shoes that run smaller in number than Ultraboost 19 — size up half: Nike Air Force 1, adidas Superstar, adidas Stan Smith, adidas NMD R1, adidas NMD R1 Primeknit, Converse Chuck Taylor Ox, New Balance 574, and New Balance 990 V5. If you wear AF1 in 10, take Ultraboost 19 in 10.5.
Boot-style models: Clarks Desert Boot, Red Wing Iron Ranger, and Red Wing Moc Toe run even smaller in number than Ultraboost 19.
Sign in to Feetlot and add a few of your other sneakers to get a personal Ultraboost 19 size recommendation.
adidas Ultraboost 19 Size Chart (US / EU / UK)
| US Men's | US Women's | UK | EU |
|---|---|---|---|
| 4 | 5 | 3.5 | 36 |
| 4.5 | 5.5 | 4 | 36.5 |
| 5 | 6 | 4.5 | 37.5 |
| 5.5 | 6.5 | 5 | 38 |
| 6 | 7 | 5.5 | 38.5 |
| 6.5 | 7.5 | 6 | 39 |
| 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 | 42.5 |
| 9.5 | 10.5 | 9 | 43 |
| 10 | 11 | 9.5 | 44 |
| 10.5 | 11.5 | 10 | 44.5 |
| 11 | 12 | 10.5 | 45 |
| 11.5 | 12.5 | 11 | 46 |
| 12 | 13 | 11.5 | 46.5 |
| 13 | 14 | 12.5 | 47.5 |
Common Sizing Mistakes
- Ordering Ultraboost 19 in your AF1 or Superstar size. Both AF1 and Superstar run about half a size smaller in number than Ultraboost 19. If you wear AF1 or Superstar in 10, take Ultraboost 19 in 10.5.
- Assuming Ultraboost 19 fits the same as other adidas casual shoes. Superstar and Stan Smith are in the AF1 cluster — half a size smaller in number than Ultraboost 19. The Ultraboost runs closer to AJ1 and AM90.
- Assuming Ultraboost 19 fits differently than AJ1 or Dunk Low. All three round to the same size in the Feetlot model. Same number in all.
How Feetlot Computes These Numbers
Every adidas Ultraboost 19 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). The result: sizing advice that holds up no matter how unusual a wardrobe is.