Full metrication with the passage of the Standards of Weights and Measures Act, 1956,Act No. 89 of 1956 . now replaced by the Standards of Weights and Measures Act, 1976:Act No. 60 of 1976. these Acts quote the legal conversion factors for imperial units to SI units. Exact conversions can be made for customary units if they had previously been defined in terms of imperial units: however, even when legally defined, the value of a unit could vary between different localities.
