12畳 = 19.4 m² (209 sq ft · 5.88 坪)
From a Japanese listing
Tatami size varies by region — the same “6畳” can differ by 15%+. Listings legally must also show ㎡.
12畳
🏠 A compact studio (1R/1K) — fine for one person.
㎡ is the legal size. 畳/坪 are traditional — always cross-check the ㎡ figure.