Tsubo, m² & Tatami Converter
Convert between tsubo, square meters (m²), tatami (jo), ares, hectares, square feet and acres all at once. You can also work it out from a room’s length × width.
Enter by
1. Choose a unit and enter a number
Choose a unit and enter a number to see the same area in other units right away.
Unit
Size of 1 tatami
Tatami sizes vary by region and building. The “○ jo” in Japanese property listings uses the real estate standard (1.62 m²).
2. Results
Choose the number of decimal places. The copy buttons copy just the number.
- Square meters
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- Tatami mats (Real estate standard)
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- Ares
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- Hectares
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- Square feet
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- Acres
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Decimal places
Everything is calculated on this device. The numbers you enter are never sent anywhere.
1 tsubo is calculated as 400/121 m² (about 3.305785 m²), and 1 square foot as 0.09290304 m².
Tatami counts are estimates based on the tatami size you chose.
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How to use
1. Choose a unit and enter a number
Tap “Tsubo” under “Unit” and type the area in the box below. As you type, “Results” below shows the same area in square meters, tatami mats, ares and other units.
In the left panel, click “Tsubo” under “Unit” and type the area in the box below. As you type, “Results” on the right shows the same area in square meters, tatami mats, ares and other units.
2. Choose the tatami size
Under “Size of 1 tatami”, below the area field, tap “Edoma”. The tatami count in “Results” below is recalculated using the Edoma size (176 × 88 cm). Japanese property listings use the “Real estate standard”.
Under “Size of 1 tatami” in the left panel, click “Edoma”. The tatami count in “Results” on the right is recalculated using the Edoma size (176 × 88 cm). Japanese property listings use the “Real estate standard”.
3. Get the area from length × width
Tap “Length × width” at the top and enter the room’s measurements in the “Length” and “Width” boxes. “Results” below shows the room’s area in m², tsubo and tatami. You can choose “m”, “cm” or “ft” as the length unit.
Click “Length × width” at the top and enter the room’s measurements in the “Length” and “Width” boxes. “Results” on the right shows the room’s area in m², tsubo and tatami. You can choose “m”, “cm” or “ft” as the length unit.
4. Copy the results
Tap the copy button to the right of a result to copy just the number (like “9.72”). “Copy all results” copies the area in every unit at once.
Click the copy button to the right of a result to copy just the number (like “9.72”). Click “Copy all results” to copy the area in every unit at once.
Great for
Making sense of Japanese property listings
Convert the m², tsubo or tatami on floor plans and listings into units you know, and compare the size with your current home or other places.
People looking for a place to rent or buy in Japan
Finding out how many tatami a room is
Just enter the length and width you measured with a tape measure to see the room’s size in m², tsubo and tatami.
People moving or rearranging a room
Knowing the size of land in tsubo
Convert the m² on Japanese land registry or sales documents into tsubo, and ares or hectares of farmland into m² or tsubo.
People buying, selling or inheriting land in Japan
Comparing with square feet and acres
Turn sizes in square feet (ft²) or acres into m² or tsubo—or the other way round—to picture how big a home really is.
People moving to or from Japan, and international students
Good to know before you start
- Tatami counts are estimates based on the tatami size you chose. Actual tatami mats can differ slightly from room to room.
- Length × width gives the area of a rectangular room. For an L-shaped room or an irregular plot, split it into rectangles, calculate each one and add them up.
- For contracts and land registration, the m² figure written in the documents is the official area.
Tsubo, square meters and tatami sizes
The tsubo is a traditional Japanese unit of area based on the old length unit “shaku”: a square 6 shaku (about 1.82 m) on each side. Since 1 shaku is defined as 10/33 m, 1 tsubo is 400/121 m² (about 3.3058 m²). To convert m² to tsubo, multiply by 121/400 (0.3025). Contracts and land registration use m², but tsubo is still widely used in Japan to describe the size of land and homes.
Tatami mats vary in size by region and building: Kyoma/Honma, Chukyoma, Edoma, Danchima and more. In Japanese property listings, the rule is to count “1 jo = at least 1.62 m²” no matter the actual mat size, written as “○畳” or “○帖”. Both kanji are read “jo” and mean the same size; 帖 is often used for Western-style rooms without tatami.
FAQ
Answers to common questions about converting tsubo, square meters and tatami.
Are the numbers I enter sent anywhere?
No. All calculations happen in the browser on your device, and the numbers you enter are never sent to a server.
How many m² is 1 tsubo?
400/121 m², or about 3.31 m². For example, 30 tsubo is about 99.17 m². To go from m² to tsubo, multiply by 0.3025 (100 m² is 30.25 tsubo).
How many tatami is 1 tsubo?
People often say “1 tsubo = 2 tatami”, but it’s exactly 2 only with Chukyoma mats (6 × 3 shaku). It depends on the mat size: about 2.04 with the real estate standard (1.62 m²), about 2.13 with Edoma, and about 1.81 with Kyoma.
Is there a difference between 畳 and 帖?
No, both are read “jo” and mean the same size. 畳 is usually used for Japanese-style rooms with tatami, and 帖 for Western-style rooms without tatami. In property listings, both count at least 1.62 m² as 1 jo.
Which should I choose: Kyoma, Chukyoma, Edoma or Danchima?
To convert the tatami count in a listing or floor plan, choose “Real estate standard”. For actual tatami mats in a Japanese-style room, older homes in western Japan often use Kyoma, the Tokai region (around Nagoya) Chukyoma, eastern Japan including the Kanto region Edoma, and public housing and apartments Danchima.
How many m² and tsubo is a 6-tatami room?
With the real estate standard (1.62 m²), it’s 9.72 m², or about 2.94 tsubo. With Edoma it’s about 9.29 m², and with Kyoma about 10.94 m². Switch “Size of 1 tatami” to recalculate instantly.
Can I work out the tatami count from a room’s length and width?
Yes. Click “Length × width” at the top and enter the measurements in “Length” and “Width”. You can enter them in m, cm or ft. For example, 3.6 m × 2.7 m is 9.72 m², which is 6 tatami by the real estate standard.
How many tsubo are an are and a hectare?
1 are (a) is 100 m², or 30.25 tsubo, and 1 hectare (ha) is 10,000 m², or 3,025 tsubo. The Japanese farmland unit “tan” is about 10 ares (300 tsubo), but it isn’t included in this tool.
How are square feet and acres calculated?
1 foot is exactly 0.3048 m, so 1 square foot is 0.09290304 m². 1 acre is 43,560 square feet (about 4,046.86 m²). For example, 1,000 square feet is about 92.9 m², or about 28.1 tsubo.
Do the results have small rounding errors?
No. Numbers that don’t divide evenly are kept as exact fractions and only rounded to the decimal places you chose at the very end. Very small values (such as 0.0003 ha) are shown with extra decimal places so they don’t turn into 0.
Is it free?
Yes, it’s free. No sign-up needed, and there are no ads.
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