👟 Brand to Brand
On to UGG Shoe Size Conversion
Switching from On to UGG? On runs true to size and UGG runs large, so the size you order changes. Here's the full chart.
A On 9 works out to a UGG 8.5 — about half a size down. The chart below has every size.
On → UGG: size down half a size
A On 9 is a UGG 8.5.
Find your On size on the left, read across for UGG:
| On size | UGG size | UK | EU | Foot (cm) |
|---|---|---|---|---|
| 6.5 | 6 | 5.5 | 37 | 23.5 |
| 7 | 6.5 | 6 | 38 | 24.3 |
| 7.5 | 7 | 6.5 | 38.5 | 24.7 |
| 8 | 7.5 | 7 | 39.5 | 25.1 |
| 8.5 | 8 | 7.5 | 41 | 25.9 |
| 9 | 8.5 | 8 | 41.5 | 26.3 |
| 9.5 | 9 | 8.5 | 42.5 | 26.7 |
| 10 | 9.5 | 9 | 43 | 27.1 |
| 10.5 | 10 | 9.5 | 43.5 | 27.5 |
| 11 | 10.5 | 10 | 44 | 27.9 |
| 11.5 | 11 | 10.5 | 44.5 | 28.3 |
| 12 | 11.5 | 11 | 45.5 | 28.7 |
| 12.5 | 12 | 11.5 | 46 | 29.1 |
| 13 | 12.5 | 12 | 47 | 29.5 |
| 13.5 | 13 | 12.5 | 47.5 | 29.9 |
| 14 | 13.5 | 13 | 48 | 30.3 |
| 14.5 | 14 | 13.5 | 49 | 31.1 |
| 15 | 14.5 | 14 | 49.5 | 31.5 |
⚠️ Fit varies by model. On (On Running) runs true to size for most, with a snug, performance fit. UGG runs about half a size large and moulds to the foot — size down half, or a full size for slippers.
UGG to On → · On chart · UGG chart · Brand finder
What is a On 9 in UGG?
A On 9 is about a UGG 8.5 — they share a foot length of roughly 26.3 cm (UK 8, EU 41.5).
Do On and UGG fit the same?
No — On runs true to size and UGG runs large, so size down half a size when you switch.
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