# Why Diamonds Are Measured in Carats

Weight in carats is one of the defining factors when buying diamonds. And the final price depends on the weight.

5-Minute Crafts is going to tell you what a carat is, why it’s used to measure diamonds, and how to know how many carats a diamond weighs.

### What a carat is

The carat is a measure of mass used in jewelry to measure the weight of diamonds. 1 carat is 200 mg.

A lot of people think that a carat stands for the size of a diamond. But in fact, the length and the width are measured in millimeters. If a diamond is round, the diameter is used. For example, a round diamond that weighs 1 carat is around 6.4 mm.

### How carat was invented

The word carat has a long history. It comes from the Italian carato that is from the Arabic qīrāṭ which, in turn, comes from Greek where it means “carob seed.”

Carob seeds have been used throughout history to measure jewelry. It was believed that there was little variance in their mass distribution. However, this was a factual inaccuracy, as their mass varies about as much as seeds of other species.

### How to know how many carats there are in a diamond?

The exact weight of a diamond depends on the cut. For example, a round diamond of a deep cut, weighing 1 carat, might look smaller than a round diamond of a different cut weighing 0.95 carats.

• 0.25 carats — diameter 4 mm
• 0.5 carats — diameter 5 mm
• 0.75 carats — diameter 5.7 mm
• 1 carat — diameter 6.4 mm
• 1.5 carats — diameter 7.4 mm
• 2 carats — diameter 8 mm
• 3 carats — diameter 9.3 mm
• 4 carats — diameter 10.2 mm
• 5 carats — diameter 11 mm
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