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Tsubo and Tatami-Mat (Jo) Area Conversion: The Basics

Here are the basics of converting "tsubo" and "jo," units commonly seen in Japanese real estate listings and floor plans, into square meters.

1 tsubo β‰ˆ 3.3 square meters

Precisely, 1 tsubo equals about 3.305785 square meters, but in practice it's commonly treated as "about 3.3 square meters."

The origin of the tsubo

Believed to derive from the old shakkanho system of measurement, defining 1 tsubo as the area of a square with sides of 1 ken (about 1.82 meters).

The advertising-standard size of a jo (tatami mat)

In real estate advertising, an industry self-regulation standard sets the minimum size of 1 "jo" (tatami-mat unit) at 1.62 square meters when calculating a listed tatami count.

Actual tatami mat size varies by region

The actual physical size of a tatami mat differs by region and building type β€” kyoma, chukyoma, edoma, danchima, and more β€” so a "6-jo" room can vary in actual size.

A rough rule of thumb

A tsubo is often used as roughly equal to two tatami mats' worth of space β€” a 6-jo room is roughly 3 tsubo, or around 10 square meters.

Official registered area uses square meters

Area used in official procedures like real estate registration is generally expressed in square meters (mΒ²); tsubo and jo are mainly used in everyday conversation and advertising for easier comprehension.

Land area is often discussed in tsubo

Especially for land, expressions based on tsubo β€” like "price per tsubo" β€” remain deeply entrenched in the real estate industry.

A quick conversion trick

To get tsubo from square meters, divide the square meter figure by about 3.3; to get square meters from tsubo, multiply the tsubo figure by about 3.3 β€” both give a quick rough estimate.

Why multiple units are still mixed together

Even after the metric system was introduced in the Meiji era, units based on the older shakkanho system β€” like tsubo and jo β€” remained deeply embedded in everyday life, especially in real estate. While legally the metric system is standard, these older units continue to be used alongside it for practical ease of understanding.

A caution when comparing listings

Comparing room sizes by tatami-mat count alone can be misleading due to differences in actual tatami size, so for an accurate comparison, it's worth also checking the square-meter (mΒ²) figure.

Frequently Asked Questions

How many square meters is 1 tsubo?

Precisely, about 3.305785 square meters β€” in practice, it's generally treated as "about 3.3 square meters."

Roughly how many square meters is a 6-jo room?

Using the advertising-standard 1.62 square meters per jo, that works out to about 9.7 square meters β€” though the actual figure varies somewhat with real tatami size and room shape.

Why can the same "6-jo" label feel like different room sizes?

Because actual tatami mat sizes differ across kyoma, edoma, danchima, and other regional standards. Treat the advertised jo count as a rough guide, and check the square-meter figure too if it matters to you.

What does "price per tsubo" mean?

The price of land or a building divided by its area in tsubo β€” a commonly used figure for comparing regional real estate prices.