Which On models run small? Cloud 5 often feels shorter/narrower (half up is common). Cloudmonster is usually the more forgiving last — start TTS, half up only for width, thick socks, or long-run swelling.
Quick scan: runs small — Cloud 5; runs big — —; narrow — —; true to size — Cloudmonster, Cloudsurfer.
Use the converter (model → model) or open a full guide.
Looking for clothing? Cut/line guides are under Clothes. · Women’s sizing for verified gender offsets.