What if I am between sizes in the On Cloudmonster?

Between sizes in the On Cloudmonster: start with TTS default; half up for wide feet, thick socks, or long-run swell. Width and sock volume often matter more than splitting a half size.

How do the On Cloudmonster fit for wide or narrow feet?

More forefoot room than Cloud 5 for many; still not a max-wide last — thick socks may need half up Advice: TTS default; half up for wide feet, thick socks, or long-run swell

Should I size up in the On Cloudmonster for thick socks or break-in?

Break-in: None. Thick socks add volume — try the sock you will wear with the usual size advice before jumping a full size. See the thick socks & boot break-in guides.

Cloudmonster

Does Cloudmonster run big or small?

Cloudmonster is usually On’s more forgiving last and fits true to size for many. Wide feet, thick socks, or long-run swelling may still p…

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Partial · methodology

True to Size TTS default; half up for wide feet, thick socks, or long-run swell

PartialLast reviewed 2026-08-12

Runs smallTrue to sizeRuns big

Length usually matches a typical street size for this category.

Width note: More forefoot room than Cloud 5 for many; still not a max-wide last — thick socks may need half up

What size should you buy?

Your usual size

Interactive suggestion based on this model’s fit offset (+0 US). Always confirm with a retailer return policy.

Brand / model converter · Compare brands · Guides

Measured / size chart (cm)

Numbers only when sourced. Empty fields stay blank — we do not invent mm.

On size chart (foot-length cm)
US M	UK	EU	cm
6	5.5	38.5	23.4
6.5	6	39	23.9
7	6.5	40	24.4
7.5	7	40.5	24.9
8	7.5	41	25.3
8.5	8	42	25.8
9	8.5	42.5	26.1
9.5	9	43	26.6
10	9.5	44	27
10.5	10	44.5	27.4
11	10.5	45	27.8
11.5	11	45.5	28.3
12	11.5	46	28.7
13	12.5	47.5	29.6

Chart cm is approximate foot length for label matching — not a lab internal cut. Use the cm converter to map foot length across brands.

Fit scenarios

Between sizes: Start with the advice above, then confirm with the between-sizes / half-size guide.
Width: Length and width are separate — see wide feet / narrow fit.
Socks & volume: Thick hiking or winter socks change volume — socks & orthotics · socks & fit.

Width: More forefoot room than Cloud 5 for many; still not a max-wide last — thick socks may need half up
Break-in: None

Summary

Cloudmonster is usually On’s more forgiving last and fits true to size for many. Wide feet, thick socks, or long-run swelling may still prefer half up. Some guides still call the toebox shallow — that TTS vs half-up split keeps Partial confidence.

Sources: Gallery Streetwear (Cloudmonster TTS and roomier On last) · OD’s On (Cloudmonster half up — narrower toe box) · Believe in the Run Cloudmonster (TTS for some; shallow toebox — between sizes go up) · methodology

Fit depth guide

Conditional: (1) Already in On/Hoka running sizes → start TTS. (2) Wide forefoot / thick socks / race-week swell → half up. (3) Coming from snug Cloud 5 → try Cloudmonster at TTS first; do not copy Cloud 5 size-up habits blindly.

Heel lockdown at TTS is usually secure — jumping a full size often creates slip. Use the converter with Cloud 5 as a sibling reference when you own both.

Fit reports vary by foot shape, socks, and colorway. Confidence on this row is medium — use the on-page fit survey or feedback with sources; we do not invent crowd percentages.

What size did you take?

Anonymous fit check for On Cloudmonster. Helps future readers — we never invent crowd stats.

Community results stay private until 25 responses for this page — no fake percentages.

Prefer email? Fit feedback.

FAQ

Does the On Cloudmonster run big or small?: True to Size. TTS default; half up for wide feet, thick socks, or long-run swell Cloudmonster is usually On’s more forgiving last and fits true to size for many. Wide feet, thick socks, or long-run swelling may still prefer half up. Some guides still call the toebox shallow — that TTS vs half-up split keeps Partial confidence.
What size should I buy in the On Cloudmonster?: TTS default; half up for wide feet, thick socks, or long-run swell
What if I am between sizes in the On Cloudmonster?: Between sizes in the On Cloudmonster: start with TTS default; half up for wide feet, thick socks, or long-run swell. Width and sock volume often matter more than splitting a half size.
How do the On Cloudmonster fit for wide or narrow feet?: More forefoot room than Cloud 5 for many; still not a max-wide last — thick socks may need half up Advice: TTS default; half up for wide feet, thick socks, or long-run swell
Should I size up in the On Cloudmonster for thick socks or break-in?: Break-in: None. Thick socks add volume — try the sock you will wear with the usual size advice before jumping a full size. See the thick socks & boot break-in guides.

Generic US / UK / EU / cm reference

Secondary Mondopoint-style table. Prefer the brand chart in Measured / size chart (cm) when converting. Primary system: US_M.

US	UK	EU	cm
6	5.5	39	24.0
6.5	6	39.5	24.5
7	6.5	40	25.0
7.5	7	40.5	25.5
8	7.5	41	26.0
8.5	8	42	26.5
9	8.5	42.5	27.0
9.5	9	43	27.5
10	9.5	44	28.0
10.5	10	44.5	28.5
11	10.5	45	29.0
11.5	11	45.5	29.5
12	11.5	46	30.0
13	12.5	47.5	31.0

Where to buy

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