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Asics 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 · Gel-Kayano 31 Check current prices · Cloudmonster

(paid link)

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

Asics → On chart

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

Asics UScmOn USOn EU
6.023.46.038.5
6.523.96.539.0
7.024.47.040.0
7.524.97.540.5
8.025.38.041.0
8.525.88.542.0
9.026.19.042.5
9.526.69.543.0
10.027.010.044.0
10.527.410.544.5
11.027.811.045.0
11.528.311.545.5
12.028.712.046.0
13.029.613.047.5

How this Asics → On chart actually maps

This page starts from Asics centimeters. Asics US 10 is 27.0 cm and the nearest On US is also 10 (EU 44). The printed ladder is 1:1 from US 6 (23.4 cm) through US 13 (29.6 cm). The wear-box “Asics 10 ≈ On 10.0” is that Asics-side match. On model pages on this site also list 27.0 cm at US 10. The chart does not apply Cloud 5’s +0.5 converter offset.

Gel-Kayano 31 is TTS in length when you pick the right width (2E/4E rather than guessing with length); Gel-1130 is the same length-offset family. On’s three linked lasts disagree: Cloudmonster and Cloudsurfer are +0 in length; Cloud 5 runs small and narrow (most size up half; wide feet especially). A chart-matched Kayano 10 can still feel short in Cloud 5 and fine in Cloudmonster at the same US 10.

Convert from the Asics size that fits in length. Do not copy Cloud 5’s half-up onto Cloudmonster, and do not jump On to 10.5 because Kayano felt snug — that is an Asics width-letter problem. Half a size on this table is 26.6 → 27.0 → 27.4 cm. Spend it on Cloud 5’s offset or on Kayano 2E, not on both at once.

Model fit matters

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

Asics: Gel-Kayano 31 · Gel-1130

On: Cloudmonster · Cloud 5 · Cloudsurfer

Also compare Asics to: Brooks

Check prices: Asics On (paid link)

FAQ

How do I convert Asics shoe size to On?
Match by foot length in centimeters on each brand’s chart. Example: Asics US 10 ≈ On US 10.0 (about 27.0 cm). Then adjust for the specific model’s fit (runs big/small/narrow).
Is a Asics 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.