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Karat Purity

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Karat Gold Purity

A measure of gold purity on a 24-part scale, where 24 karat represents pure gold and lower karat values indicate gold alloyed with other metals.

Definition

Karat purity measures how much of a gold item is actually gold, on a 24-part scale where 24 karat represents essentially pure gold. Lower karat values mean the gold has been alloyed with other metals, usually to add strength and durability that pure gold lacks on its own.

This matters practically because two pieces of jewellery that look identical can contain very different amounts of actual gold, which directly affects both durability and resale value. Convert between karat values and purity percentages with the Karat Purity Converter.

Formula

Purity % = (Karat ÷ 24) × 100

Worked Example

22 karat gold, common in jewellery across South Asia and the Middle East, works out to (22 ÷ 24) × 100 = 91.67% pure gold, with the remaining 8.33% made up of other metals like silver, copper, or zinc. By comparison, 14 karat gold, more common in Western mass-market jewellery, is only (14 ÷ 24) × 100 = 58.33% pure.

Key Things to Know

  • Higher karat isn't automatically "better", it's a trade-off between purity and durability, and the right choice depends on whether the item is for everyday wear or investment purposes.
  • Hallmarking stamps (like "916" for 22K) indicate purity directly. "916" means 91.6% pure, which corresponds to 22 karat, a common shorthand used on jewellery markings in several countries.
  • Gold price quotes are almost always for 24K purity. When comparing the value of an item against the daily gold rate, you need to adjust for its actual karat rather than assuming the quoted price applies directly.
  • The alloy metals used affect colour, not just strength. White gold, rose gold, and yellow gold at the same karat level contain the same proportion of pure gold, just mixed with different alloy metals to achieve the different tones.

Frequently Asked Questions

24K gold is 99.9% pure with essentially no other metals mixed in, while 22K is about 91.7% pure gold alloyed with roughly 8.3% other metals, usually silver, copper, or zinc. 22K is harder and more durable, which is why it's the standard for jewellery in many markets, while 24K is softer and more prone to scratching and bending.
Pure 24K gold is quite soft, making it impractical for jewellery that needs to hold intricate shapes and withstand daily wear. Alloying it down to 22K, 18K, or 14K adds strength and durability at the cost of some purity, and the trade-off is deliberate rather than a sign of lower quality.
They're spelled similarly but measure completely different things, karat (with a K) measures gold purity on a 24-part scale, while carat (with a C) measures the weight of gemstones, where one carat equals 0.2 grams. Confusing the two is a common mistake, especially since some regions spell gold purity as "carat" as well.
18K is a popular middle ground, offering 75% gold purity with enough durability for daily wear, while 14K trades some purity for even greater hardness at a lower price point. The right choice depends on your priority between purity, durability, and budget rather than there being one objectively correct answer.
Multiply the current gold price per gram by the item's weight, then by its purity percentage (karat ÷ 24) to estimate the pure gold value, though the actual resale price also depends on craftsmanship, brand, and making charges. The [Karat Purity Converter](/karat-purity-converter/) handles the purity percentage calculation directly.