👟 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.
On runs 0.5 size larger than UGG, so you may need to size down when switching.
Size up 0.5 moving to UGG
UGG runs smaller — order half a size larger than your On size.
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 |
| 6.5 | 6 | 5.5 | 37.5 | 23.9 |
| 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 | 7.5 | 7 | 40 | 25.5 |
| 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 | 13.5 | 13 | 48.5 | 30.7 |
| 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 10.5 in UGG?
A On 10.5 is about a UGG 10 — they share a foot length of roughly 27.5 cm (UK 9.5, EU 43.5).
Do On and UGG fit the same?
Not quite — UGG runs about 0.5 size smaller than On.
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