Compare apartment sizes given in m², tsubo, or tatami

The job

Japanese real-estate listings mix units: rooms in tatami (jo), floors in m², land in tsubo. To compare two options honestly you need them in the same unit.

How to do it

Enter the number, pick its unit, and read all four conversions at once. When tatami is involved, choose the standard — ad listings legally mean at least 1.62 m² per jo, but a Kyoto house's mats can be 1.82 m².

• Quick sanity anchors: 1 tsubo ≈ 3.31 m² = 2 tatami of the ad-rule size; 6 jo ≈ 9.7–10.9 m² depending on region.
• 1 m² ≈ 10.76 sq ft — handy when a floor plan arrives from a US source.

Worked example

A 6-jo room on the ad-rule standard is 9.72 m²; the same 6 jo in Kyoma mats is 10.94 m² — over a square meter of difference from the same number. A 70 m² apartment is 21.2 tsubo.

Limits

Tatami figures describe the mat area only — closets, kitchen floors, and wall thickness are not counted as jo. Listings sometimes round jo upward, and balcony or common areas never count toward the room figure.