How Many Mm Width of a 1 Carat Ideal Cut Diamond?


While thinking of purchasing a diamond, one of the most important points to keep in mind is the carat size or weight of the stone. The carat weight itself can have a big impact on the cost of a diamond; leave alone the other C’s (Cut, Clarity, and Color). 

In this article, we will be discussing things about diamond carats, their importance and in depth mm width of a 1 carat ideal cut diamond. And the conversion of a carat to other measurable quantities and so on. But before all these, let us have a general idea about the origin of the term carat and what it means.

Diamond Carat Weight


The term “Carat” originated mainly from the idea of carob seeds. This seed was used in the past as a means to measure gemstones and jewelry weights. As it was believed that they had little to no mass distributions to them. But it was not the right, as later it was found that the carob seeds are the same as any other seeds present there. And their mass distribution also differs from each seed to other like those other species.

The newly formulated term “Carat” simply is a derived constant quantity to measure the weight of the diamonds. Before during the 1570s, each country used to have its specific carat formulation. Later on in the year of 1907, at the Fourth General Conference of Weights. It was declared as an agreement that a carat should be equivalent to 200 milligrams, precisely. Thus the system changed and carat or more specifically modern carat had a universal measurement which was and is followed all over the world.

The carat weight of a diamond has a huge impact on the price of the stones. Simply speaking, larger carat is equal to a more expensive stone. It is because diamonds that are larger in carat quantities tend to be bigger. And hence are more desirable and rare in making. However on must not also neglect the cut, color, and clarity aspects of the stone. Two different stones of the same carat weight can hugely differ in their costs and values if these other aspects of grading are taken into consideration.

The Idea of Carat Size Charts

We, humans, are clever species. We tend to simplify everything according to our self convenience. From time to time and in the present too, whenever there come complicated relations and conversion criteria. We classify and chart up the information to ease things up.

In the case of diamonds to there are specific size charts about each shape and cut respectively. Here we will be noting down the millimeter to carat weight size conversion chart of ideal diamond cuts. Please have a look to have an easier understanding.

Diamond Size Chart (conversion from mm to carat weight)


4.0 mm diameter = 0.25 ct.

5.1 mm diameter = 0.5 ct.

5.8 mm diameter = 0.75 ct.

6.4 mm diameter = 1.0 ct.

6.9 mm diameter = 1.25 ct.

7.3 mm diameter = 1.5 ct.

7.7 mm diameter = 1.75 ct.

8.1 mm diameter = 2.0 ct.

8.5 mm diameter = 2.25 ct.

8.9 mm diameter = 2.5 ct.

9.0 mm diameter = 2.75 ct.

9.3 mm diameter = 3.0 ct.

9.5 mm diameter = 3.25 ct.

9.75 mm diameter = 3.5 ct.

9.9 mm diameter = 3.75 ct.

10.1 mm diameter = 4.0 ct.

From the above mentioned chart, we can see that the width of a 1 carat Ideal Cut diamond is about 6.4 to 6.5 mm in diameter.

Tips for Buying A Perfect Carat Of A Diamond


With all the information and carat weights and millimeters and this and that. One can get confused about which carat size they should go for. But there is no reason to worry, as we here will be suggesting some basic guidelines by following. Which one may recognize the perfect diamond according to its size and carat weight. The rules are as follows:

  • One should always consider that a balance should always be maintained between the cost and the carat size of the diamond. Big carat size simply does not mean the best diamond and the best diamond simply does not mean the costliest one.
  • One should always go for the “eye- clean” diamonds. What we mean by this is that though it is the right thing. That one should always listen to the experts and the gemologists for the best advice they can provide. The self preference factor cannot simply be neglected. If a customer or buyer finds a diamond to look beautiful and clean through their naked eye. Chances are others too will find the diamond equally beautiful and mesmerizing; be it of any size or carat weight.
  • The diamond cuts are a deceiving factor of a diamond, meaning one may find diamonds of the same carat weight to look big or small. This usually happens due to the varieties of shapes and facet cut qualities that these stones come with. It is best suggested that one should go for such a diamond, which showcases a perfect blend between its shape, size, sparkle, carat weight, and cost.

Why Ideal Cut Diamonds Are Said To Be The Best?


Ideal cut diamonds are those diamonds that are best in terms of their brilliance, cut proportions, angles, and symmetry ratings. They are believed to reflect all the light that falls on them and hence showcase the most extreme amount of sparkle. Every country has its terms and conditions for their specific ideal cuts but the Tolkowsky-cut is the most common one among all.

General Overview of Mm Width of a 1 Carat Ideal Cut Diamond

general overview of mm width of a 1 carat ideal cut diamond

Simply put, people all over the world have a common misconception, that is, they think that the diamond carat weight is exactly proportional to the size of the diamond. In other words, they think that a diamond of 2 carats will be exactly equivalent to two 1 carat ideal cut diamond in terms of their size. But that is not the case. In the size chart mentioned above, we can already see the diameter listings of different carat sizes. The diameter of a 2-carat diamond is 8.2 mm which is nowhere the double of that of the diameter of a 1 carat ideal cut diamond 6.4 mm. Hopefully, this example will clear up this misconception of the readers and customers.

One should always go for the perfect blend in between the cost, the size, the look and feel, and the carat size for the diamond they wish to buy. We know it is not an easy task but that is the reason we here provide the information and guidelines for the buyers to follow. We wish the best of luck to everyone for their diamond shopping!!