How Big is One Carat Diamond (Actual Size Pictures & Chart)

Sharif Khan
Sharif Khan
Last Updated    EST 
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While shopping for diamonds, most jewelry buyers face one challenge: the ideal carat weight.

Carat refers to a unit of measurement for diamond weights; one carat equals 0.2g. Here, distinguishing between carat and karat is necessary since these terms are common in the jewelry industry. Carat is almost exclusively used in the diamond trade, while karat is widely used in the gold trade. Karat refers to the purity score of a piece of gold or gold jewelry. To put it into perspective, a 24 Karat ring is made up of almost 100% gold.

For some diamond shoppers, carat differences do not mean much if the other three aspects of the Four Cs—cut, clarity, and color—have been taken care of. Carat variations reflect on the overall price of a diamond; the higher the carat weight, the pricier the gem. More importantly, a diamond carat impacts the beauty of the stone.

So, how big is a one carat diamond, and how to choose the best one?

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How Big Is a One carat Diamond

0.2 grams may not look or sound heavy, but it is probably equivalent to the weight of an average raindrop or a quarter of a raisin. But in the diamond industry, numbers mean a lot. As mentioned, a slight variance in carat comes with significant price variations, ceteris paribus. How big a one carat diamond looks depends on various aspects, some of which have been explained as follows:

1 carat diamond size chart in mm

The Diamond Cut

The size of a one carat diamond significantly depends on the cut. For clarity purposes, the words “cut” and “shape” have been used interchangeably under this section, though the shape is one of the elements of a diamond cut.

A one carat round brilliant diamond has a width of 6.5 mm. This is reasonably big, though not as big as the oval, pear, or marquise cuts of similar weight. A one carat oval cut diamond measures around 7.55 by 5.54mm. As for marquise cuts, one carat comes to roughly 10mm x 4.75mm. The marquise and oval shapes will look bigger than the brilliant round shape depending on where the diamond is set. The marquise, pear, and oval diamond cuts are known for their impressive illusions of size. Therefore, they are ideal for customers looking for something that appears larger without necessarily investing in extra carats.

On the other hand, some diamond shapes appear small even with higher carat weights—the Asscher cut is a perfect example. When polishing Asscher diamonds, cutters emphasize their surface area, which explains why Asscher cuts have the largest surface area.

The following table gives an overview of the size of a one carat diamond across popular cuts:

Diamond Cut


Round Brilliant Cut


Emerald Cut


Princess Cut


Marquise Cut


Heart shaped Diamonds


Asscher Cut


Trillion Diamonds


Pear shaped Cuts


Radiant Cuts


Oval Cuts


When shopping for a one carat diamond, it is likely to come across the term “spread,” which refers to the size relative to the carat weight. Therefore, the marquise and oval shapes tend to be more “spready.”

Generally, the size of a one carat diamond can be enhanced by choosing fancier shapes. Avoid cushion cut diamonds since they tend to be deep set, due to which much of their weight is hidden underneath their surface, making them look relatively small.

However, it is not easy to tell a one carat diamond from, say, a 1.5 carat one, especially if the diamonds look similar in all other aspects. It does not matter whether one is viewing the stone online or in physical displays; their best bet would be to rely on a diamond certification from a reputable lab.

The Setting in a Ring

The size of a one carat diamond also depends on how the diamond is set in a ring. For instance, a one carat diamond will look larger on a platinum band because the white color of the band will reflect the diamond, enhancing its size.

Still, on the setting, always insist on thinner bands, for they are remarkable in accentuating the size of the gem.

Halo ring settings are also preferable for those looking to enhance the size of their one carat diamonds. In a halo setting, the diamond is the center gemstone surrounded by a ring of micro pavé diamonds. The paves are included to enhance the size of the center diamond.

But what if a buyer thinks the one-carat diamond they selected looks way larger than they desire? There is no need to worry; they can experiment with some settings to diminish its size. For instance, a bezel setting is known to make diamonds look smaller than they are. In bezel settings, the diamond in the metal edge is surrounded. These are popular for enhancing the shape of a diamond and not necessarily its size. The apparent absence of accent stones makes the diamond look even smaller.

However, numerous ways exist to enhance a one carat diamond’s size in a bezel setting. Most notably, one can choose fewer or more slender prongs to hold the stone in place to maximize the surface of the diamond that shows, thereby making it appear bigger.

Diamond Color

Color psychologists believe that brighter colors create an illusion of space; the same principle holds for diamonds. Yellow, blue, green, and soft pink diamonds often appear bigger. Generally, insist on colors that reflect maximum light from all the edges of the diamond.

Color also goes hand in hand with clarity. If a one carat diamond has visible flaws, the blemishes will reduce its ability to absorb and reflect light. Therefore, the diamond may look smaller than it is.

One carat Round Diamond Actual Look

1 to 4 Carats Diamond Rings

How Much Does a 1 Carat Diamond Cost

As far as prices are concerned, please refer to our full diamond prices chart. Additionally, also check how much 1 carat diamond costs

There is no definite answer to this question since several factors dictate the price of diamonds. Also, diamond prices do not increase linearly; instead, they increase exponentially. Therefore, one cannot expect the price of a 1 carat diamond to be half that of a 2 carat diamond, even if other factors remain constant.

Cuts and shapes also determine the price of diamonds. Generally, the round brilliant cuts are the most expensive. The cushion and princess cuts follow closely, with marquise shapes being cheaper.

Colors and clarity ratings are other factors that influence the price of a one carat diamond. Red and white diamonds are the most expensive. The fancy appearance often drives those who go for red diamonds, while those who opt for white are perfectionists looking for a flawless stone.

According to statistics, a high percentage of diamond shoppers prefer the 1 carat diamond, which factor alone affects the stone’s overall cost.

A one carat diamond may not look too big on screen, which is why one can only appreciate its size when buying it. However, it is possible to enlarge or diminish the size of a one carat diamond without necessarily reducing its carat weight. It all comes down to how one plays around with the other aspects of the Four Cs.