Does the Adidas Ultraboost 23 Run Big or Small?
The Adidas Ultraboost 23 (Running) runs true to size with a wide toe box. See the US/UK/EU/CM conversion chart and what size to order.
How the Ultraboost 23 fits
The Adidas Ultraboost 23 (Running) runs true to size. Compared with a true-to-size sneaker, order your usual size. It has a wide toe box and high arch support, with a primeknit textile upper that shapes how the fit settles over time.
Ultraboost 23 fit specs
| Category | Running |
| Length Fit | True to Size |
| Toe Box Profile | Wide |
| Arch Support | High |
| Upper Material | Primeknit Textile |
Size conversion chart
US, UK, EU and centimetre equivalents. Use it alongside the fit note above to land the right size in the Ultraboost 23.
| US | UK | EU | CM |
|---|---|---|---|
| 4 | 3 | 36 | 22 |
| 4.5 | 3.5 | 36.5 | 22.5 |
| 5 | 4 | 37 | 23 |
| 5.5 | 4.5 | 37.5 | 23.5 |
| 6 | 5 | 38 | 24 |
| 6.5 | 5.5 | 38.5 | 24.5 |
| 7 | 6 | 39 | 25 |
| 7.5 | 6.5 | 40 | 25.5 |
| 8 | 7 | 41 | 26 |
| 8.5 | 7.5 | 41.5 | 26.5 |
| 9 | 8 | 42 | 27 |
| 9.5 | 8.5 | 42.5 | 27.5 |
| 10 | 9 | 43 | 28 |
| 10.5 | 9.5 | 44 | 28.5 |
| 11 | 10 | 44.5 | 29 |
| 11.5 | 10.5 | 45 | 29.5 |
| 12 | 11 | 46 | 30 |
| 12.5 | 11.5 | 46.5 | 30.5 |
| 13 | 12 | 47 | 31 |
| 13.5 | 12.5 | 47.5 | 31.5 |
| 14 | 13 | 48 | 32 |
| 14.5 | 13.5 | 48.5 | 32.5 |
| 15 | 14 | 49 | 33 |
Frequently asked questions
Does the Adidas Ultraboost 23 run big or small?
The Adidas Ultraboost 23 runs true to size. Compared with a true-to-size sneaker, order your usual size.
What size should I get in the Adidas Ultraboost 23?
If you normally wear a US 10, target a US 10 in the Ultraboost 23. A US 9 foot maps to about US 9 and a US 11 to about US 11, because the model runs true to size.
Is the Adidas Ultraboost 23 wide or narrow?
It has a wide toe box with extra room across the forefoot. Upper material is primeknit textile, which affects how much it gives over time.
What kind of arch support does the Adidas Ultraboost 23 have?
Arch support is rated high on the Ultraboost 23 (Running). Expect a structured, cushioned ride.
Compare the Ultraboost 23 to another shoe
Select both shoes to see your sizing verdict
| Spec | Adidas Ultraboost 23 | Shoe B |
|---|---|---|
| Length Fit | True to Size | — |
| Toe Box Profile | Wide | — |
| Arch Support | High | — |
| Upper Material | Primeknit Textile | — |