On Size Chart: US, UK, EU & CM Conversion (Men’s & Women’s)

Sep 10, 2026

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Marco Bianchi is a personal shopping advisor and sizing specialist at Cecile Milan Journal, focused on how fit differs from one brand — and one model — to the next. Years spent fitting customers across Nike, Adidas, New Balance and other major sneaker brands inform his brand-to-brand sizing comparisons, model-specific fit notes and practical advice for readers converting their usual size between brands.

On runs true to size for most people, with a half-size US-to-UK offset similar to Adidas and New Balance. Use the tables below to convert between US, UK, EU and CM (foot length) sizing before you order. If you’re between two sizes, see our On Cloud sizing guide.

Men’s On Size Chart

Foot length (CM) is the most reliable column if you’re converting from a brand outside the US/UK/EU system.

Men’s sizing — US, UK, EU, CM
US	UK	EU	CM
7	6.5	40	25
7.5	7	40.5	25.5
8	7.5	41	26
8.5	8	42	26.5
9	8.5	42.5	27
9.5	9	43	27.5
10	9.5	44	28
10.5	10	44.5	28.5
11	10.5	45	29
11.5	11	46	29.5
12	11.5	47	30
12.5	12	47.5	30.5
13	12.5	48	31

Women’s On Size Chart

On women’s sizes are offered on a separate last, not just a shifted men’s size — always convert using the women’s table below rather than subtracting from the men’s chart.

Women’s sizing — US, UK, EU, CM
US	UK	EU	CM
5	3	36	22
5.5	3.5	36.5	22.5
6	4	37	23
6.5	4.5	37.5	23.5
7	5	38	24
7.5	5.5	38.5	24.5
8	6	39	25
8.5	6.5	40	25.5
9	7	40.5	26
9.5	7.5	41	26.5
10	8	42	27
10.5	8.5	42.5	27.5
11	9	43	28

How to Use This Chart

Measure your foot length in centimeters from heel to the tip of your longest toe, in the afternoon when feet are slightly swollen, and match it to the CM column — this is more accurate than converting from a size you wear in another brand. On’s CloudTec sole is quite firm underfoot, so unlike more cushioned rivals, fit here is driven mainly by the upper’s shape rather than midsole give.

Frequently Asked Questions

Does On run true to size?

Yes, most On models, including the Cloudmonster and Cloud 5, run true to size. Some racing-focused models fit slightly snugger through the midfoot.

Is On sizing the same for men and women?

No. On women’s shoes are built on a dedicated women’s last, not simply a relabeled men’s size. Use the women’s table above rather than converting from the men’s chart.

What EU size is a US men’s 10 in On?

A US men’s 10 converts to EU 44, UK 9.5, and 28 cm foot length in On sizing.