20坪 = 66.1 m² (712 sq ft · 20.0 坪)
From a Japanese listing
Tatami size varies by region — the same “6畳” can differ by 15%+. Listings legally must also show ㎡.
20坪
🏠 Family-sized apartment or a small house footprint.
㎡ is the legal size. 畳/坪 are traditional — always cross-check the ㎡ figure.