How do I convert UGG shoe size to On?

Match by foot length in centimeters on each brand’s chart. Example: UGG US 10 ≈ On US 10.0 (about 27.0 cm). Model fit can still differ — check model guides.

Is a UGG US 10 the same as a On US 10?

Not always. Labels can map to slightly different foot lengths. Use the cm column, then adjust for the specific model’s fit.

UGG 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 · Classic Mini Check current prices · Cloudmonster

(paid link)

Your UGG size (US)

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

UGG → On chart

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

UGG US	cm	On US	On EU
6.0	23.4	6.0	38.5
6.5	23.9	6.5	39.0
7.0	24.4	7.0	40.0
7.5	24.9	7.5	40.5
8.0	25.2	8.0	41.0
8.5	25.8	8.5	42.0
9.0	26.1	9.0	42.5
9.5	26.6	9.5	43.0
10.0	27.0	10.0	44.0
10.5	27.4	10.5	44.5
11.0	27.8	11.0	45.0
11.5	28.2	11.5	45.5
12.0	28.7	12.0	46.0
13.0	29.6	13.0	47.5

Model fit matters

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

UGG: Classic Mini · Classic Short II · Tasman Slipper · Classic Ultra Mini

On: Cloudmonster · Cloud 5 · Cloudsurfer

Also compare UGG to: Crocs

Check prices: UGG On (paid link)

FAQ

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