Dictionary of Units / Measurements

# Areas Unit

The S I unit of area is the square metre. To change any of these other units of area into their equivalent values in square metres use the operation and conversion factor given. Those marked with # are exact. Other values are given to an appropriate degree of accuracy. Where some uncertainty is indicated it means that a good idea of the size of the unit can be given but that a better value would depend upon knowing the period and/or culture in which the unit was being used. Note than in matters concerned with land measurements, for the most accurate work, it is necessary to establish whether the US survey measures are being used or not.

 acres                 x 4046.856 422 4 # ares                   x 100 # circular inches    x 0.000 506 707 479 hectares             x 10 000 # hides                  x 485 000 (with wide variations) roods                  x 1011.714 105 6 # square centimeters     x 0.000 1 # square feet (UK and US)        x 0.092 903 04 # square feet (US survey)        x 0.092 903 411 613 square inches          x 0.000 645 16 # square kilometres      x 1 000 000 #   square metres          1 square miles           x 2 589 988.110 336 # square millimetres     x 0.000 001 # squares (of timber)    x 9.290 304 # square rods (or poles) x 25.292 852 64 # square yards           x 0.836 127 36 # townships              x 93 239 571.972