916 gold is 22 carat gold. The number 916 is used to denote the purity of gold in the final product, i.e. 91.6 grams of pure gold in 100 gram alloy. The figure 916 is basically 22/24 (22 carat by 24 carat). In a similar manner, 958 gold is 23 carats (23/24) and 750 gold is 18 carats (18/24).