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Area

All-in-one unit converter

Enter one area value. See every other unit together.

0 to 1 trillion. Decimals and fullwidth digits are accepted. Commas are ignored regardless of position or number. No exponent notation.

Your input stays in your browser. It is never sent or saved.

Conversion results

Shows the other five units, rounded to 10 significant digits as an estimate.

  • Tsubo

    0.3025tsubo

  • Tatami (jō)

    0.6172839506jō

  • Square feet (ft²)

    10.76391042ft²

  • Ares (a)

    0.01a

  • Hectares (ha)

    0.0001ha

How to use

  1. Enter an area and select its unit. Results update automatically when either changes.
  2. Compare the other five units and use the copy button for the result you need.
  3. Choose Number + unit or Number only. Copied numbers use the same rounding as the displayed results.

Example

100 m² equals 30.25 tsubo, approximately 61.72839506 jō, 1 a and 0.01 ha. One tsubo is 400/121 m² (approximately 3.305785124 m²), and one square foot is 0.09290304 m².

Calculation and limitations

  • Factors: 1 tsubo = 400/121 m²; 1 jō = 1.62 m²; 1 ft² = 0.09290304 m² (international foot); 1 a = 100 m²; 1 ha = 10,000 m². Only area conversion is available here.
  • This tool fixes one tatami unit (jō) at 1.62 m². Japanese real-estate advertising rules specify at least 1.62 m² per advertised jō, not a nationwide physical mat size. Actual sizes vary by region, standard and whether area is measured inside walls or to wall centres.
  • Calculations use JavaScript floating-point numbers without rounding intermediate results. Displayed results are rounded to 10 significant digits with trailing zeros removed. Small numbers are expanded into decimal notation. Floating-point precision can affect results.
  • Fullwidth digits and decimal points are normalized internally. All halfwidth and fullwidth commas are removed before validation, regardless of position or number (1,0000 becomes 10000; 1,,000 becomes 1000). Commas in decimal digits are also ignored; comma-only input is invalid. Your input is not rewritten while typing. On blur, the integer part is grouped with commas without rounding your decimal digits. Negative, invalid or oversized values show an error. Empty input hides results. Values too small for the numeric calculation range also show an error.
  • Displayed and copied numbers use the same comma grouping and a period for the decimal point. Copy requires localhost or HTTPS and browser permission. Results are estimates; verify original documents and required precision for contracts, land registration or surveying.

Conversion references