Area Unit Converter (m², tsubo, tatami mats, acres, and more)
Convert area units — m², cm², km², tsubo (坪), tatami mats (畳), ares (a), hectares (ha), acres, ft², yd², and mi² — into every unit at once from a single value, including traditional Japanese real-estate units.
Area conversion base values (1 unit = how many square meters)
| Unit | Base value |
|---|---|
| Square meter (m²) | 1 m2 = 1 m² |
| Square centimeter (cm²) | 1 cm2 = 0.0001 m² |
| Square kilometer (km²) | 1 km2 = 1,000,000 m² |
| Tsubo (坪) | 1 tsubo = 3.305785 m² |
| Tatami mat (畳, Edo-ma standard) | 1 jou = 1.6562 m² |
| Are (a) | 1 a = 100 m² |
| Hectare (ha) | 1 ha = 10,000 m² |
| Acre | 1 acre = 4,046.8564224 m² |
| Square foot (ft²) | 1 ft2 = 0.09290304 m² |
| Square yard (yd²) | 1 yd2 = 0.83612736 m² |
| Square mile (mi²) | 1 mi2 = 2,589,988.110336 m² |
Tips
- Enter one value and pick its unit, and all 11 area units — m², tsubo, tatami mats, acres, and more — are converted at the same time, so there's no need to look each one up separately.
- Tsubo and tatami mats (jou) are traditional Japanese units still used in real-estate and construction listings today, handy for comparing a property's size against other units.
- Tatami mat size varies by region — Edo-ma, Kyo-ma, and Danchi-ma standards all differ. This tool uses the most common Edo-ma standard (1 jou = 1.6562 m²).
- Acres and square feet, commonly used in overseas real-estate listings, are converted too — handy when comparing property sizes abroad.
Frequently Asked Questions
Side Note — The history behind tsubo, tatami mats, and the acre
The tsubo comes from Japan's traditional shakkanho system of measurement. It is defined as the area of a square with sides of 6 shaku (about 1.818 meters), which works out to exactly the area of two tatami mats. Even after the metric system was introduced during the Meiji era, the tsubo remained deeply entrenched as the unit for describing land area, and Japanese real-estate ads and homebuilder catalogs still commonly quote a "price per tsubo" today.
The size of a single tatami mat is not standardized nationwide. Edo-ma (about 1.6562 m²), common in the Kanto region, Kyo-ma (about 1.824 m²), common in the Kansai region, and Danchi-ma (about 1.445 m²), common in apartment blocks, can differ substantially depending on the region and construction method. A room labeled "6 tatami mats" can therefore vary in actual size by nearly 50% between properties, so when apartment-hunting it is safer to check the floor area in square meters as well as the mat count.
The acre originated in medieval England, said to be based on the area of farmland a team of oxen could plow in a single day with a wooden plow. Today it remains in everyday use across English-speaking countries — the US, UK, and Canada — for describing large tracts of land such as farms, ranches, and golf courses. One acre is about 4,047 square meters, roughly a third of the playing field at the Tokyo Dome (about 1.3 hectares).