👟 Brand to Brand
UGG to On Shoe Size Conversion
Switching from UGG to On? UGG runs large and On runs true to size, 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 down 0.5 moving to On
On runs larger — order half a size smaller than your UGG size.
Find your UGG size on the left, read across for On:
| UGG size | On size | UK | EU | Foot (cm) |
|---|---|---|---|---|
| 6.5 | 7 | 5.5 | 37 | 23.5 |
| 6.5 | 7 | 5.5 | 37.5 | 23.9 |
| 7 | 7.5 | 6 | 38 | 24.3 |
| 7.5 | 8 | 6.5 | 38.5 | 24.7 |
| 8 | 8.5 | 7 | 39.5 | 25.1 |
| 8 | 8.5 | 7 | 40 | 25.5 |
| 8.5 | 9 | 7.5 | 41 | 25.9 |
| 9 | 9.5 | 8 | 41.5 | 26.3 |
| 9.5 | 10 | 8.5 | 42.5 | 26.7 |
| 10 | 10.5 | 9 | 43 | 27.1 |
| 10.5 | 11 | 9.5 | 43.5 | 27.5 |
| 11 | 11.5 | 10 | 44 | 27.9 |
| 11.5 | 12 | 10.5 | 44.5 | 28.3 |
| 12 | 12.5 | 11 | 45.5 | 28.7 |
| 12.5 | 13 | 11.5 | 46 | 29.1 |
| 13 | 13.5 | 12 | 47 | 29.5 |
| 13.5 | 14 | 12.5 | 47.5 | 29.9 |
| 14 | 14.5 | 13 | 48 | 30.3 |
| 14 | 14.5 | 13 | 48.5 | 30.7 |
| 14.5 | 15 | 13.5 | 49 | 31.1 |
| 15 | 15.5 | 14 | 49.5 | 31.5 |
⚠️ Fit varies by model. UGG runs about half a size large and moulds to the foot — size down half, or a full size for slippers. On (On Running) runs true to size for most, with a snug, performance fit.
On to UGG → · UGG chart · On chart · Brand finder
What is a UGG 10.5 in On?
A UGG 10.5 is about a On 11 — they share a foot length of roughly 27.5 cm (UK 9.5, EU 43.5).
Do UGG and On fit the same?
Not quite — On runs about 0.5 size larger than UGG.
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