Metric carat ct

Symbolct
SystemMetric (non-SI)
QuantityMass
Value in SI1 ct = 200 mg (exact)
Defined / adopted1907 (4th CGPM)

About the Metric carat

The metric carat of exactly 200 milligrams is the standard unit for weighing gemstones and pearls. Before standardisation, carats varied from city to city, based originally on carob seeds. It should not be confused with the karat, which measures gold purity in 24ths.

Related Units