Browser-only conversion
m² ↔ tsubo ↔ tatami ↔ m ↔ mm converter + reference table
Everything is calculated in SI (m / m²). Tatami is always accurate because you input the tatami size.
Show Japanese units (tsubo / tatami)
Display
Mode
URL sync: ?mode=length / ?mode=area
Converter
Recent inputs
Japanese unit basis
Tsubo and tatami are added only when the Japanese units toggle is ON.
Tsubo
1 tsubo = 3.305785 m²
This tool uses 1 tsubo = (20/11 m)²
Tatami
0.1–3m
Enter tatami size to enable tatami conversion.
Tatami basis
Results
Common units are shown at once
SI
Imperial
Japanese
Breakdown
Reference table
Generate a printable A4/Letter table on the same page
Max 500 rows
Reference table
Generation settings
Preview
Shows the first 20 rows
Notes & definitions
- Tatami sizes differ by region. This page uses your input size as the basis.
- This tool is an aid for calculation and does not replace design, legal, contract, or safety requirements.
- Preset values are examples and may vary by conditions.
Definitions
Calculations are based on SI units (m / m²).
Tsubo uses 1 tsubo = (20/11 m)² = 3.305785 m².