How Are Diamond Earrings Measured?

Diamond earrings might only be a small accessory, but they certainly give a statement and work perfectly with any outfit and occasion. Small but mighty. But how do you know what size diamond earrings you should be buying? How are diamond earrings measured?

Diamond earrings are measured in millimeters and the individual carat weight of each earring. For example, if you had a 0.25-carat diamond stud, the diameter would measure as 4.1mm, which is relatively small. If you had a diamond earring which is 3 carats, the diameter would measure as 9.3mm, which is much larger.

Diamond earrings are sold showing the total carat weight, which is the combined carat weight of the pair of earrings, not the weight for just one of them. That means if you see a pair of 1-carat diamond earrings, each individual earring is actually 0.5 carats instead of both earrings being 1 carat each. This usually won’t be displayed so ensure what you are buying; it is best to ask the seller to specify this.

What is the average diamond earring size per carat weight?

Diamondstuds.com created this nice diamond earring size guide (For a round shape diamond stud), and it follows as:

Size guide

The sizing guide given above is only an average and will not necessarily be the same for every diamond earring that you purchase.

2.00 CTW
If the earring pair’s total weight of a diamond is 2.00 carat, then each individual diamond will weigh 1.00 carat, and the average diameter will measure as 6.5mm.

1.50 CTW
If the earring pair’s total weight of a diamond is 1.50 carat, then each individual diamond will weigh 0.75 carat, and the average diameter will measure as 5.8mm.

1.25 CTW
If the earring pair’s total weight of a diamond is 1.25 carat, then each individual diamond will weigh 0.62 carat, and the average diameter will measure as 5.55mm.

1.00 CTW
If the earring pair’s total weight of a diamond is 1.00 carat, then each individual diamond will weigh 0.50 carat, and the average diameter will measure as 5mm.

0.75 CTW
If the earring pair’s total weight of a diamond is 0.75 carat, then each individual diamond will weigh 0.375 carat, and the average diameter will measure as 4.67mm.

0.62 CTW
If the earring pair’s total weight of a diamond is 0.62 carat, then each individual diamond will weigh 0.31 carat, and the average diameter will measure as 4.3mm.

0.50 CTW
If the earring pair’s total weight of a diamond is 0.50 carat, then each individual diamond will weigh 0.25 carat, and the average diameter will measure as 4.1mm.

0.40 CTW
If the earring pair’s total weight of a diamond is 0.40 carat, then each individual diamond will weigh 0.20 carat, and the average diameter will measure as 3.8mm.

0.33 CTW
If the earring pair’s total weight of a diamond is 0.33 carat, then each individual diamond will weigh 0.165 carat, and the average diameter will measure as 3.5mm.

0.25 CTW
If the earring pair’s total weight of a diamond is 0.25 carat, then each individual diamond will weigh 0.125 carat, and the average diameter will measure as 3.2mm.

For more precise measurements, take a look at our Actual Diamond Size Chart. It helps answer common questions like:

How big are 12mm earrings?
12mm Emerald, Radiant, and Oval cut diamond earrings are 5 carats.

How big are 10mm earrings?
10mm Round cut diamond earrings are 3.5 carats.

How big are 8mm earrings?
8mm Round cut diamond earrings are 1.75 carats.

How big are 7mm earrings?
7mm Round cut diamond earrings are 1.24 carats.

How big are 6mm earrings?
6mm Round cut diamond earrings are .75 carats.

How big are 5mm earrings?
5mm Round cut diamond earrings are .50 carats.

How big are 4mm earrings?
4mm Round cut diamond earrings are .23 carats.

How big are 1/2 carat diamond earrings?
1/2 carat Round cut diamond earrings are 5.2mm

 

Does the size of the diamond depend on the shape of the diamond earrings?

The size of the diamond can sometimes depend on the shape of the earring’s diamond that you are purchasing. A different diamond shape such as round, oval, square, heart, etc. means that it will measure slightly different. A round diamond stud that has a total carat weight of 0.50 will on average measure as 4.1mm. But, if you were to purchase instead a square diamond stud which has a total carat weight of 0.50 it will on average measure as 3.5mm, which is smaller.

What is a good size for diamond earrings?

A good size for diamond earring is 1ct on each ear or 2cttw. However, it is a personal choice when it comes to the size of the diamond earrings that you want to purchase. But the cost of the diamond earrings can also be a factor when it comes to choosing the size of the diamond earrings that you wish to purchase. The bigger diamond earring you buy, the more expensive it will be and vice versa. So smaller will always cost less.


Summing it all up. Diamond earrings are measured by the weight of the carat. The weight of the carat will determine an average diameter. The diamond will be sold as a total carat weight. Make sure that you are aware of the individual carat for each earring, this will help to show you the size of each stud.

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Carl Jones

Carl has been involved in the jewelry business since his youth. Growing up in South Africa his parents were jewelers who worked in the industry for decades.

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