Japanese area converter
Convert square meters, tsubo, and a selected tatami reference or custom mat size.
Your inputs
Enter an amount and select the source and target units. Results update as you edit.
Calculations run in your browser. Inputs are not saved or sent to analytics.
How it works
- Converted estimate = × Conversion factor
- Tsubo (坪) = 400/121 m²
- Tatami: custom dimensions = ×
- Worked example: Convert 10 tsubo to square metres using the standardized shaku definition. This gives area only; a tatami count still depends on the selected mat convention or dimensions.
- 10 × (20 ÷ 11)² ≈ 33.057851 m².
Input and formula key
Your result
Complete the inputs to see your result.
Assumptions and limitations
The 1.62 m² advertising reference is a minimum convention, not a universal physical mat size or a measured room area.
Sources
- Nagoya University — 1951 Measurement Act Enforcement Act, articles 4–5 Sources reviewed: 2026-10-05
- Real Estate Fair Trade Council — Tatami advertising-area rule Sources reviewed: 2026-10-05
