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Brooks to On size conversion

Match sizes by foot length (cm), then check model fit — US labels alone can mislead across brands.

Chart match · verify brand charts
Check current prices · Ghost 16 Check current prices · Cloudmonster

(paid link)

Full converter (model + shoes you own) · Reverse: On → Brooks

Brooks → On chart

Static conversion table (crawlable). Interactive tool above uses the same cm matching.

Brooks UScmOn USOn EU
6.023.56.038.5
6.524.06.539.0
7.024.57.040.0
7.525.07.540.5
8.025.48.041.0
8.525.98.542.0
9.026.29.042.5
9.526.79.543.0
10.027.110.044.0
10.527.510.544.5
11.027.911.045.0
11.528.411.545.5
12.028.812.046.0
13.029.713.047.5

How this Brooks → On chart actually maps

Brooks US 10 is 27.1 cm and the nearest On US is also 10 (EU 44). The printed ladder is 1:1 from US 6 (23.5 cm) through US 13 (29.7 cm). The wear-box “Brooks 10 ≈ On 10.0” is that centimeter match — it does not say Ghost 16 and Cloud 5 share a last, and it does not apply Cloud 5’s +0.5 offset. On model pages list 27.0 cm at US 10; here the source column is Brooks, so US 10 stays 27.1 and still lands on On 10.

Ghost 16 is TTS as a high-volume daily trainer — use Brooks B/D/2E instead of oversizing length. Glycerin 21 matches Ghost-style TTS length. On’s three linked lasts disagree: Cloudmonster and Cloudsurfer are +0; Cloud 5 runs small and narrow (most size up half; wide feet especially). A chart-matched Ghost 10 in 2E can still feel short in Cloud 5 and roomy in Cloudmonster.

Convert from the Brooks size that fits in length with the correct width letter. Do not copy Cloud 5’s half-up onto Cloudmonster, and do not copy a Ghost 2E habit onto Cloud 5 as extra length on top of the +0.5. Half a size on this table is 26.7 → 27.1 → 27.5 cm. Spend it on Cloud 5’s offset or on Brooks width, not on both plus a second On model jump.

Model fit matters

Even when charts match, lasts differ. Check these guides:

Brooks: Ghost 16 · Glycerin 21

On: Cloudmonster · Cloud 5 · Cloudsurfer

Check prices: Brooks On (paid link)

FAQ

How do I convert Brooks shoe size to On?
Match by foot length in centimeters on each brand’s chart. Example: Brooks US 10 ≈ On US 10.0 (about 27.1 cm). Then adjust for the specific model’s fit (runs big/small/narrow).
Is a Brooks US 10 the same as a On US 10?
Not always. Labels can map to slightly different foot lengths. Use the cm column, then check model guides on both brands.
Which direction should I read first?
Start from the brand you already wear, then open the model fit pages linked below — lasts differ even when charts match.

Clothes sizing uses a separate compare path.