Gold purity explained: 22K vs 21K vs 18K

When you look at a gold price list in Bangladesh, you will usually see several rows for the same day: 22K, 21K, 18K, and sometimes traditional/"shanko" gold. The karat number tells you how much of the item is actually gold versus other metals mixed in for strength. 24K is (near) pure gold, roughly 99.9% purity. It is soft, and rarely used for everyday jewelry because it scratches and bends easily. 22K is about 91.6% gold, the most common standard for jewelry in Bangladesh and much of South Asia, balancing purity with durability. 21K (87.5%) and 18K (75%) trade some purity for a harder, more durable piece, often at a lower price point. This matters practically in two ways. When you are buying, the karat tells you what you are actually paying for. Always ask which karat a quoted price refers to, since a lower-karat piece will look similar but contain meaningfully less gold. When you are selling or exchanging old jewelry, jewelers will test the purity (often with an acid test or an electronic tester) rather than take your word for the karat stamp, and the price offered will reflect that measured purity, not the original stamp. BAJUS (Bangladesh Jewellers Samity) publishes daily reference rates by karat, which is why our gold price page always lists rates side by side by purity rather than a single number: "the gold price" genuinely depends on which gold you mean.