Match sizes by foot length (cm), then check model fit — US labels alone can mislead across brands.
Chart match · verify brand charts(paid link)
Full converter (model + shoes you own) · Reverse: Brooks → Asics
Static conversion table (crawlable). Interactive tool above uses the same cm matching.
| Asics US | cm | Brooks US | Brooks 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 | 25.3 | 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 | 28.3 | 11.5 | 45.5 |
| 12.0 | 28.7 | 12.0 | 46.0 |
| 13.0 | 29.6 | 13.0 | 47.5 |
ASICS US 10 is 27.0 cm on this table; Brooks’ nearest US is 10 (EU 44). US 10.5 is 27.4 cm → Brooks 10.5. Gel-Kayano 31 and Gel-1130 versus Ghost 16 and Glycerin 21 are all daily-trainer length stories that this site calls TTS — if you pick the width letter. The chart’s 1:1 US line is the easy part.
Kayano 31’s own page says use 2E/4E rather than guessing length; Ghost 16’s title is TTS with B/D/2E. A chart-matched 10 in standard D/B that pinches is a width miss, not proof the centimeter column is wrong. 1130 is a lifestyle mesh that many find more forgiving than Kayano’s wrap; Glycerin is the softer Brooks trainer, not a different length rule.
Do not copy Kayano 14 lifestyle sizing into this bridge. Start at Brooks US 10 from ASICS 10 / 27.0 cm, then spend the decision on B/D/2E (Ghost) or 2E/4E (Kayano), not on a 4 mm half size (27.0 → 27.4 cm) that loosens the heel.
Even when charts match, lasts differ. Check these guides:
Asics: Gel-Kayano 31 · Gel-1130
Brooks: Ghost 16 · Glycerin 21
Check prices: Asics Brooks (paid link)
Clothes sizing uses a separate compare path.