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How to convert tsubo to square meters
The tsubo (坪) is the traditional Japanese unit for land and floor area. One tsubo is exactly 400/121 square meters, about 3.3058 m² — a square of about 1.82 m × 1.82 m, or roughly two tatami mats.
Formula: m² = tsubo × 3.305785
Example: 30 坪 × 3.305785 = 99.17 m²
Going back is simpler, because 121/400 is a short number: one square meter is exactly 0.3025 tsubo.
Formula: tsubo = m² × 0.3025
Example: 100 m² × 0.3025 = 30.25 坪
Features
- Instant answer — type tsubo in the From box and see square meters as you type
- Exact factor — 1 坪 = 400/121 m², not a rounded 3.3, so land sizes stay right
- Swap (⇄) — turn m² into tsubo in one click, with no rounding error
- Pyeong too — the Korean pyeong (평) is in the same list; it is the same size
- Bulk convert a list — paste many plots or rooms, one per line or a column from Excel; each line keeps its place
- Three ways to show the list — Results only, Value and result or CSV (for Excel), with 0 to 6 Decimal places
- Copy results or Download CSV — and it all runs in your browser; nothing is uploaded
Tsubo to square meters table
| Tsubo (坪) | Square meters (m²) |
|---|---|
| 1 | 3.31 |
| 2 | 6.61 |
| 5 | 16.53 |
| 10 | 33.06 |
| 15 | 49.59 |
| 20 | 66.12 |
| 25 | 82.64 |
| 30 | 99.17 |
| 35 | 115.7 |
| 40 | 132.23 |
| 50 | 165.29 |
| 60 | 198.35 |
| 80 | 264.46 |
| 100 | 330.58 |
| 150 | 495.87 |
| 200 | 661.16 |
Values are rounded to 2 decimal places.
Square meters to tsubo
Because 1 m² is exactly 0.3025 坪, these numbers are exact.
| Square meters (m²) | Tsubo (坪) |
|---|---|
| 25 | 7.5625 |
| 40 | 12.1 |
| 45 | 13.6125 |
| 60 | 18.15 |
| 80 | 24.2 |
| 100 | 30.25 |
| 120 | 36.3 |
| 150 | 45.375 |
| 200 | 60.5 |
Tatami (畳) and tsubo
Room sizes in Japan are often given in tatami mats (畳, jō): a "6畳" room, an "8畳" living room. A tsubo is about 2 tatami. But a tatami is not one fixed size — it depends on the region and the building:
| Tatami type | Size | One mat | A 6畳 room |
|---|---|---|---|
| Kyōma 京間 (Kyoto, west Japan) | 191 × 95.5 cm | 1.824 m² | 10.94 m² |
| Chūkyōma 中京間 (Nagoya area) | 182 × 91 cm | 1.656 m² | 9.94 m² |
| Edoma 江戸間 (Tokyo, east Japan) | 176 × 88 cm | 1.549 m² | 9.29 m² |
| Danchima 団地間 (apartment blocks) | 170 × 85 cm | 1.445 m² | 8.67 m² |
| Real-estate rule | — | 1.62 m² | 9.72 m² |
The real-estate rule: in Japanese property ads, one 畳 must be at least 1.62 m². So when an ad says "洋室 6畳", the room is about 9.72 m² or more, which is 2.94 坪. Old houses can have bigger or smaller mats, so measure the room when the exact size matters.
Tatami is not in the converter on purpose: with five sizes in use, one number would be wrong for most rooms. Use the table above, or convert the room's m².
Where the number comes from
A tsubo is a square of 1 ken × 1 ken (間). One ken is 6 shaku (尺), and since 1891 a shaku has been 10/33 m. So 1 ken = 20/11 m ≈ 1.818 m and 1 tsubo = (20/11)² = 400/121 m².
Japan's measurement law has required square meters for official use since the 1960s, but tsubo is still common for land plots, house floor areas and shops. Land prices are often given per tsubo (坪単価); to get the price per m², multiply by 0.3025.
The Korean pyeong (평) and Taiwan's ping (坪) are the same size as the tsubo.
Tsubo in daily life
- A house plot in a Tokyo suburb: 30 坪 = 99.17 m²
- A family house floor area: 35 坪 = 115.7 m²
- A one-bedroom flat (1LDK): 40 m² = 12.1 坪
- A quick guess: tsubo × 3.3 = m², and m² ÷ 3.3 = tsubo (exact: × 0.3025)
Bulk convert a list of tsubo to square meters
Comparing plots or rooms? Paste their sizes under Bulk convert a list and every line is converted at once — a bulk tsubo to square meters converter on the same page.
- Paste values one per line, separated by commas or spaces, or a column copied from Excel or Google Sheets
- Lines keep their order; a line with text, like "Plot A 42.5", converts its number — when a line has two numbers, the first one counts
- Show results only to paste back into your sheet, value and result, or CSV
- Click Swap first to turn a list of m² into tsubo
Frequently asked questions
How many square meters is 1 tsubo?
1 tsubo is 3.305785 m² (exactly 400/121 m²). For a quick guess, use 3.3.
How many tsubo is 100 m²?
100 m² is exactly 30.25 tsubo, because 1 m² = 0.3025 tsubo.
How many square meters is a 6畳 room?
It depends on the mats. By the real-estate rule (1.62 m² per 畳) it is 9.72 m². With Tokyo-size mats it is about 9.29 m², and with Kyoto-size mats about 10.94 m².
Is 1 tsubo the same as 2 tatami?
Roughly. Two mats of the real-estate size are 3.24 m², a little less than one tsubo (3.31 m²). Two Kyoto-size mats are 3.65 m², a little more.
Is a tsubo the same as a Korean pyeong?
Yes. Both are 400/121 m², about 3.3058 m². Taiwan's ping (坪) is the same too.
Can I convert many sizes at once?
Yes. Paste them under Bulk convert a list — one per line, or a column from Excel — and all of them are converted together. Copy the results or download them as a CSV file.
Is my data sent anywhere?
No. The conversion runs in your browser, on your own device.
Related tools
- Pyeong to Square Meters — the Korean 평, with apartment sizes
- Square Meters to Square Feet — m² for US listings
- Japanese Era Converter — Reiwa and Heisei years
- Square Footage Calculator — the area of a room from its size
- Unit Converter — every unit in one place
How to use it
- Type a size in tsubo in the From box — the square meters appear straight away
- Click Swap (⇄) to convert square meters to tsubo
- Change the units to convert to square feet, pyeong or any other area unit
- Many values at once? Paste them under Bulk convert a list — one per line, or a column from Excel — and copy the results or download a CSV
