What’s the difference between carats, karats, carrots, and carets?  They all sound the same, but they have very unique meanings.  And two of them, carats and karats, are commonly used words in the jewelry industry.


Used to describe the mass of a diamond and other gemstones, a carat is a measure of weight.  One carat is equal to 0.2 grams or approximately 0.007 ounces.  The name, carat, comes from ancient times when carob beans were used on a balancing scale to measure the weight of light objects like gemstones.  A carob bean doesn’t weigh much but, more importantly, carob beans are very consistent in their weight and size.  Each one weighs about 0.007 ounces (about the same weight as a paperclip).  Another way to think about it is that it takes about 142 beans to make one ounce.

balancing scale

1 carob bean = 1 carat diamond

Historically, weighing light objects wasn’t done consistently. The carob bean was used throughout the Middle East and Europe.  Grains of wheat or rice were used elsewhere.  And the carat was used to weigh other things besides gemstones.   There wasn’t a standard carat weight that was used in all countries.  But in 1907, the 4th General Conference on Weights and Measures adopted the “metric carat”, equal to 0.2 grams or 200 mg, as the official and world-wide measurement for diamonds and gemstones.


The term, karat, is usually used to indicate the fineness of a gold alloy.  It is a measure of purity.  Twenty-four karat gold signifies 100% pure gold.  So, using your knowledge of fractions, you can determine that 18 karat gold has 75% gold and 25% other metals. (You can also see my previous blog on metal alloys.).  Fourteen karat gold has 58% gold and 42% other metals.

Interestingly enough, the measure, karat, came from the German carat.  The Germans had a gold coin, called a “mark”, which weighed exactly 24 carats (4.8 grams).  The purity of the gold in the coin was expressed as the number of carats of gold present in the 24-carat coin.  Somehow, the letter was changed from “c” to “k” and the karat was born.

So, what about “caret” and “carrot?”  Well, a caret is a wedge-shaped symbol indicating the place where something is to be inserted.  And a carrot?  Well, I’ll let Bugs Bunny explain that one.