On Shoe Size Chart
On's own published size chart, covering a 22cm to 31.5cm foot. Every figure below is keyed to a measured foot length rather than converted from another size number. Open the calculator with On selected to read it against all 35 brands at once.
Does On run small?
No. By its own size chart, On sizes in line with most brands in both men's and women's sizes. A 27 cm foot is a men's US 9 in On and in 22 of 34 other brands' charts. Charts show how a brand means its sizes to fit, not how any one shoe feels, so read On's own fit advice below as well.
| Foot length | On | Most common in other brands |
|---|---|---|
| Men's, 25.5 cm | US 7.5 | US 7.5 (20 of 34) |
| Men's, 27 cm | US 9 | US 9 (22 of 34) |
| Men's, 28.5 cm | US 10.5 | US 10.5 (19 of 34) |
| Women's, 23 cm | US 6 | US 6 (14 of 33) |
| Women's, 24 cm | US 7 | US 7 (15 of 34) |
| Women's, 25 cm | US 8 | US 8 (15 of 34) |
How this is worked out: every foot length from 25 to 29 cm (men's) and 22.5 to 26 cm (women's), in 1 mm steps, is read against On's chart and the other 34 brands' charts the way the calculator reads them, rounding up between sizes. The answer is the average gap between On's size and the size the other brands give most often. See the methodology.
On men's size chart
| Foot length (cm) | US | UK | EU | JP |
|---|---|---|---|---|
| 22 | 4 | 3.5 | 36 | 22 |
| 22.5 | 4.5 | 4 | 36.67 | 22.5 |
| 23 | 5 | 4.5 | 37.33 | 23 |
| 23.5 | 5.5 | 5 | 38 | 23.5 |
| 24 | 6 | 5.5 | 38.67 | 24 |
| 24.5 | 6.5 | 6 | 39.33 | 24.5 |
| 25 | 7 | 6.5 | 40 | 25 |
| 25.5 | 7.5 | 7 | 40.5 | 25.5 |
| 26 | 8 | 7.5 | 41 | 26 |
| 26.5 | 8.5 | 8 | 42 | 26.5 |
| 27 | 9 | 8.5 | 42.5 | 27 |
| 27.5 | 9.5 | 9 | 43 | 27.5 |
| 28 | 10 | 9.5 | 44 | 28 |
| 28.5 | 10.5 | 10 | 44.5 | 28.5 |
| 29 | 11 | 10.5 | 45 | 29 |
| 29.5 | 11.5 | 11 | 46 | 29.5 |
| 30 | 12 | 11.5 | 47 | 30 |
| 30.5 | 12.5 | 12 | 47.5 | 30.5 |
| 31 | 13 | 12.5 | 48 | 31 |
| 31.5 | 14 | 13.5 | 49 | 31.5 |
On women's size chart
| Foot length (cm) | US | UK | EU | JP |
|---|---|---|---|---|
| 22 | 5 | 3 | 36 | 22 |
| 22.5 | 5.5 | 3.5 | 36.5 | 22.5 |
| 23 | 6 | 4 | 37 | 23 |
| 23.5 | 6.5 | 4.5 | 37.5 | 23.5 |
| 24 | 7 | 5 | 38 | 24 |
| 24.5 | 7.5 | 5.5 | 38.5 | 24.5 |
| 25 | 8 | 6 | 39 | 25 |
| 25.5 | 8.5 | 6.5 | 40 | 25.5 |
| 26 | 9 | 7 | 40.5 | 26 |
| 26.5 | 9.5 | 7.5 | 41 | 26.5 |
| 27 | 10 | 8 | 42 | 27 |
| 27.5 | 10.5 | 8.5 | 42.5 | 27.5 |
| 28 | 11 | 9 | 43 | 28 |
On kids' sizing
On does not publish a children's chart distinct from the standard youth scale, so we show the general children's progression rather than presenting it as On-specific. See the international shoe size chart for that scale.
How to measure for On
On uses a Mondopoint-based system where each full US size corresponds to about 1cm of foot length; measure heel-to-toe standing, using the longer foot.
On fit guidance
On running shoes generally run true to size; if between sizes, On recommends sizing up. Note: some retailers report On's UK women's sizing is mislabeled identically to men's UK sizing on certain size charts -- use the US or CM columns for the most reliable fit. On does make children's shoes: a Junior band around UK 10 to 2.5 and a Youth band around UK 3 to 5.5, including Cloud Sky, Cloudsurfer Youth and Cloudswift Kids. On does not publish a children's foot-length chart, though, and the third-party charts that do disagree with each other, so the figures shown here are the standard youth scale rather than On's own. On's own advice is to measure the longer foot and size up if between sizes, since children's feet grow quickly.
Where this data comes from
- On official size guide
- On men's and women's size chart, US/UK/EU/cm (Bergfreunde)
- On sizing detail incl. known UK labeling quirk (Absolute-Snow)
- On men's and women's foot length in cm and inches (Hibbett)
Sizing information reviewed October 2026. Manufacturers revise their charts from time to time, so always confirm against the specific model before buying.
Find your size in every brand at once. Enter your foot length in the calculator and compare On against 34 other brands side by side.
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