🔲 Tsubo Area Converter (坪 to m2)
The Tsubo Area Converter translates tsubo (坪, the traditional Japanese unit of land and floor area) into metric units (m2, hectares), imperial units (ft2, acres), and other traditional units (tatami mats, bu). One tsubo equals 400/121 square meters (approximately 3.3058 m2).
Enter tsubo (坪) to instantly convert to square meters, square feet, acres, hectares, and tatami mats. 1 tsubo = 3.3058 m2.
What is this tool?
The Tsubo Area Converter converts between tsubo (坪) and modern area units. The tsubo is the most widely used traditional Japanese unit for real estate, land, and floor area, still appearing in property listings, construction plans, and casual conversation.
One tsubo is defined as:
| Unit | Equivalent |
|---|---|
| 1 tsubo | 400/121 m2 = 3.30578 m2 (35.58 ft2) |
| 1 tsubo | 2 Edoma tatami mats (1.62 m2 each) |
| 1 tsubo | 1 bu (歩) |
| 1 hectare | 3025 tsubo (100 are) |
| 1 acre | 1224.17 tsubo |
Japanese real estate uses tsubo for both land area (tochi tsubo) and floor area (tatemono tsubo). Construction cost estimates (tsubo tan'i) are quoted per tsubo of floor area. The metric system is official, but tsubo persists in commercial practice.
How it works
The converter uses the exact legal definition of tsubo:
This comes from: 1 tsubo = 6 shaku x 6 shaku, where 1 shaku (kane-jaku) = 10/33 m. So 1 tsubo = (60/33) x (60/33) = 3600/1089 = 400/121 m2.
Conversions:
- Tsubo to m2: multiply by 3.30578
- m2 to tsubo: multiply by 0.3025
- Tsubo to ft2: multiply by 35.5832
- Tsubo to acres: multiply by 0.00081693
- Tsubo to hectares: multiply by 0.00033058
| Property Type | Tsubo | m2 | Typical Layout |
|---|---|---|---|
| 1K apartment | 7-10 | 23-33 | 1 room + kitchen |
| 1LDK apartment | 15-20 | 50-66 | 1 room + LDK |
| 2LDK apartment | 25-35 | 83-116 | 2 rooms + LDK |
| Compact house | 30-40 | 99-132 | 3 rooms |
| Standard house | 40-60 | 132-198 | 4+ rooms |
For room-level measurements, see our tatami (jo) calculator. For general area conversions (m2, ft2, acres), use the area converter. Agricultural land uses the bu (步) unit.
How to use
- Enter the area in tsubo (e.g. 30 for a typical apartment).
- The converter instantly shows m2, ft2, hectares, acres, and tatami count.
- Or switch direction: enter m2 and get tsubo.
- Use the reference table to compare with other Japanese units.
Frequently Asked Questions
Why is tsubo still used in Japanese real estate?
Despite Japan officially adopting the metric system, tsubo remains deeply embedded in real estate practice, construction cost estimation, and cultural understanding. Most Japanese people intuitively know how big "30 tsubo" feels (about 100 m2), more so than "100 square meters."
How accurate is the 1 tsubo = 3.3058 m2 conversion?
This is the exact legal definition under the Japanese Measurement Act. The value 400/121 is a rational fraction (derived from 6 kane-jaku shaku squared), giving 3.30578512... m2. Rounded to 3.3058 m2 for practical use.
What is the difference between tsubo and bu (歩)?
They are the same unit. Bu (歩, also written 布) is an older name for tsubo, primarily used in agriculture and forestry. In modern contexts, tsubo (坪) is used for real estate and floor area, while bu appears in land registration for fields.
How many tsubo is a typical Japanese house?
A standard single-family home in Japan is 30-40 tsubo (100-130 m2) of floor area. A compact city apartment might be 15-20 tsubo (50-65 m2). Luxury homes exceed 50 tsubo (165 m2).
How do I convert construction cost from per-tsubo to per-m2?
Divide the per-tsubo cost by 3.3058. For example, 700,000 yen/tsubo = 700,000/3.3058 = 211,724 yen/m2. Always use the exact factor 400/121 for precise calculations.
Tips & Advice
Construction cost per tsubo (tsubo Tanka) is the standard metric for estimating building costs in Japan. A typical house costs 600,000-800,000 yen per tsubo (2025). Total cost = tsubo_tanka x floor_area_in_tsubo.
1 tsubo = 2 tatami mats (Edoma standard). This makes converting between jo and tsubo simple: divide jo by 2. A 6-jo room = 3 tsubo.
Real estate price per tsubo is used in commercial real estate (akichi, warehouses). For residential land, square meters is more common now, but older listings still use tsubo.
Beware of "public" vs "private" area. Floor area ratios (yosekiritsu) use "private" area which may exclude corridors, balconies, and shared spaces. Always confirm which measurement system a listing uses.
Related Tools
Tatami Area Calculator
Convert tatami mats (jo) to square meters and square feet. Supports Edoma, Kyoma
Area Converter
Convert area between square meters, square feet, acres, and hectares instantly.
Bu Area Converter
Convert bu (Japanese area unit = 3.306 m2 = 1 tsubo) to square meters, square fe
Shakkanho Unit Converter
Comprehensive shakkanho (traditional Japanese measurement) converter. Convert le
Sources & References
- Japanese Measurement Act (計量法, Act No. 51 of 1992). e-Gov Japan.
- NIST Handbook 44 - Appendix B: Units and Systems of Measurement. NIST.
Last reviewed: August 2026.
Limitations
Tsubo is a traditional unit not part of the International System of Units (SI).
- In legal documents, the square meter (m2) is the official unit; tsubo is supplementary
- Historical land records may use different approximations (e.g. 3.3 m2 per tsubo)
- Construction cost per tsubo varies significantly by region, materials, and builder
For legal transactions, always refer to the square meter area stated in the property registry.