Karat vs Carat: What’s the Difference?

For jewelry lovers, the terms “karat” and “carat” can be a source of confusion. Though they sound similar (and also sound just like the vegetable), these two words have very different meanings when it comes to jewelry. In this article, we’ll explain the difference between the two terms so you can become a more informed jewelry enthusiast — and so we can solve the karat vs. carat confusion once and for all. 

What is a Karat? 

Karat (spelled with a “K”) refers to the purity of gold used in jewelry and other items. When you see a jewelry description listing the karat measure, it’s telling you the ratio of pure gold to other metals in that piece. Karat rating is important for assessing the value and longevity of gold jewelry. Higher karat gold jewelry has a richer yellow color, but it also tends to be softer and can show more signs of wear over time. Lower karat gold is more durable for everyday wear because gold becomes stronger and more durable when it’s alloyed (or mixed) with other metals.

24-karat gold is 100% pure gold. 18-karat gold contains 18 parts gold and six parts other metals, making it 75% pure gold. Lower karat numbers simply indicate that the gold is even more alloyed and therefore less pure. The most common karat grades for gold jewelry are 24K, 22K, 18K, 14K, and 10K. 

You might have seen these karat indicators stamped on gold jewelry, like on the back of a pendant or maybe on the inside of a ring band. On the other hand, you might find a GP stamp, which stands for gold plated. This means that the base metal of the jewelry is a less expensive metal like brass or copper and it has a thin layer of gold coating on top. 

This ring is made from 9k gold (37.5%) and has a clear Birmingham anchor stamp.

Gold-plated jewelry is more affordable, but it also means the piece is more susceptible to tarnishing. If there’s no stamp on a piece of jewelry, you can always get it metal tested by a professional jeweler to learn more about what it’s made of.

What is a Carat?

Carats are used to measure the weight of gemstones and pearls. One carat is equal to 200 milligrams. When referring to gemstones, the carat indicates the physical weight and size of the stone. A one-carat diamond will weigh exactly 200 mg, a 0.25-carat diamond will weigh 50 mg, and so on.

For diamonds and pearls, a higher carat weight usually indicates a larger, more valuable stone. Carat is just one of the four Cs of diamond quality (along with cut, color, and clarity) that combine to indicate the overall quality of a diamond. While a large carat diamond may be valuable, if it has a low clarity grade (meaning the stone is cloudy or has blemishes) or the color is more yellow than transparent, the overall quality of the diamond may be lower than a smaller diamond with higher clarity and better color. But all other things being equal, a one-carat diamond will always be worth more than a 0.5-carat diamond.

Karat vs Carat: Telling Them Apart

Now that you understand the differences between karat vs carat, how can you be sure which of the two terms is being referred to in a jewelry description? Here are some tips:

• When describing gold purity, it will always be karat with a “K,” like a “14K gold ring.” When describing gemstone weight, it will always be carat with a “C,” like “one-carat diamond earrings.”
• Karat is only used for gold. Other metals like silver or platinum use the term “fineness” to describe the amount of pure metal in the alloy. 
• Sometimes jewelry product descriptions will use the abbreviation “ctw” to indicate “carat total weight.” This refers to the combined weight of all of the gemstones included in a piece of jewelry — like an eternity band studded with diamonds or a diamond cluster earring.

The Bottom Line

While they sound similar, karat and carat provide very different information about jewelry. Karat indicates purity of gold, while carat measures gemstone weight. Being familiar with the distinction can help you better understand jewelry descriptions and make informed purchasing decisions. Next time you’re shopping for gold earrings or a diamond tennis bracelet, remember to look for the karat or carat specification. Understanding these key jewelry terms is an important part of being an educated jewelry enthusiast! Want to learn more jewelry tips, tricks, and insider information? Sign up for our newsletter below.