Diamond Carat Weight Explained (Critical Buying Tips)

Last Updated on August 14, 2023 by Juli "Jewels" Church

Wondering what a diamond carat is and how it affects the price of diamond?

Perfect, you're in the right place!

In this Learning Jewelry guide, you'll learn:

  • What a diamond carat is
  • How carat weight affects the price of a diamond
  • Some insider buying tips when it comes to evaluating carat weight
diamond carat explained (1)

History has it that the term carat was coined from the “carob” seed that, in fact, was the initial unit of measure for diamond traders. You may have seen another similar-sounding word, “karat” which is quite different and refers to the purity in gold. As we shall see later on, a diamond’s carat has more to do with the diamond weight rather than size or shape.

On the other hand, you’ll also get to know how a diamond cut affects the carat weight and how distinct its pricing may be due to minute differences in overall carat weight. The difference in a 1.92ct diamond and a 2.13ct diamond with similar cuts may not be as you think.

In addition to this guide specifically reviewing a diamonds cut, we've also looked at various cut sizes and how to buy rings with smaller and larger cuts. See below for links to those as well.

So, let’s dive in and find out more about diamond carat weight, including money-saving tips as well.

What is a “Diamond Carat”?

Diamond carat is a metric measurement of how much a diamond weighs. It is a pretty small measurement and one carat is equal to 1/5 of a gram, or 200 milligrams, or 0.200 gram. As you may have noticed, a carat is typically abbreviated as “ct.” One diamond carat is divided into 100 points and measurements are expressed in decimal numbers: 1.34ct., 1.00ct., 3.23cts… etc. Apart from diamonds, the carat is also a standard unit of measurement for gemstones.

How Does the Diamond Carat Weight Affect Price?

When looking at the prices of diamonds per carat weight, larger diamonds are usually more valuable. However confusing it might sound, the price of diamonds is not exactly proportional to the diamond’s weight. A big reason for this phenomenon is that larger diamonds are rare to find.

Read Also: How does clarity affect a diamond's price?

So for instance, the price per carat for a 2ct. diamond might be more than twice of four-0.50ct diamonds, even though the overall carat weight is equal. It is also important to note that as we move from one whole carat to the next, the price exponentially rises as compared to changes below one carat. For example, a 0.80ct diamond worth $800 might increase to $850 for a 0.90ct diamond but as you move to a 1.00ct diamond, the price may be a whole lot more than $900.

Here, the 1.00ct diamond is placed in a different price bracket and is mostly more attractive to buyers than the lesser carat weights. Generally, the price bracket looks like this:

- 90 – 0.99ct

- 00 – 1.49ct

- 50 – 1.99ct

- 00 – 2.49ct

And so forth.

What Is More Important — Diamond Carat Weight or Diamond Cut?

Carat weight is one major factor to key in when buying a diamond online or in local stores. Together with its cut grade, the size of a diamond can be hugely affected to the extent of what you may deem as large (mostly related to a diamond’s physical diameter). So, the question is which is more important? Should you go for a bigger carat weight or a better cut diamond? Which of the two would you rather compromise at the expense of a better quality diamond?

Honestly, I would go for a diamond cut since it is crucial to defining a diamond’s brilliance. A 0.25ct excellent cut diamond would be a reasonable option than a poorly cut 1.00ct diamond (which is obviously very costly).

For me personally, carat weight is the last thing on my mind when it comes to the 4Cs. Diamond cut will always be the first because it is the one thing that literally makes or breaks your diamond.

Not only does it control your diamond's brilliance, but having a poorly cut diamond can be detrimental to its overall durability. 

So how exactly does the diamond cut stack up against carat weight?

There are two important considerations that simplify the importance of diamond cut. Firstly, the diameter across the crown (top of the diamond) and the cut grade of the diamond.

1. Diameter Across the Crown

This is usually a measurement taken across the diameter on the top part of the diamond. It is essential to know the precise measurements of the top diameter, as it will be the part that people will see often (especially in rings). Two diamonds with the same shape and carat weight may still look different in size based on cut proportions. A deeply cut diamond has a better part of its total weight hidden in the depths. Compare such a diamond to a well-cut stone, and you’ll immediately notice the well-cut stone appear to be larger.

deep cut diamond more expensive but looks small

This effect is brought up by the difference in diameter across the top of the stones. A well-cut stone has a larger diameter and even at slightly lower carat weights, may still appear to be larger than a deeply cut diamond.

Read Also: What Does CTTW (Carat Total Weight) Mean?

2. Diamond Cut Grade

When buying a diamond (especially online), choosing the right diamond cut grade may make your stone appear larger. Since excellent cut diamonds are more brilliant, the result is a shinier stone and when viewed from the top, the stone may actually appear larger. 

Even if your carat weight is small, choosing cut grades above “Very Good” will always make your diamond appear larger than it actually is. Similarly, buying a poorly cut diamond with a larger carat weight can easily make the stone look smaller.

In a nutshell, picking a stone based on carat weight alone is a huge mistake. For me, I would consider the diamond cut first as it holds more of a diamond’s beauty than any of the other 3Cs. Additionally, you could compare diamonds at online stores like James Allen or Blue Nile and filter your search using cut grades and carat weight based on jewelry scales.

My Recommendation When It Comes to Diamond Carats

While buying a diamond with a larger carat weight may be a great option, especially when “showing off”, the size alone doesn't guarantee you the best diamond. In fact, you should buy a diamond on the basis of sparkle and brilliance. That way you’ll be able to know which of the 4Cs to consider first. 

Luckily, you can navigate through a diamond’s carat weight in ways that’ll save you lots of money. For instance, the best way to look for higher carat weights without breaking the bank is to go for carat weights just below the ideal/sweet spot carat weights. Shopping in an established online diamonds seller guarantees you abundance of options and you should definitely use that to your advantage.

Think of buying a 0.99ct diamond rather than a 1.00ct or a 1.49ct instead of 1.50ct diamonds. Visually, the diamonds would probably look the same since a 0.01ct difference is barely noticeable to the naked eye.

If you’re really pressed to hit a certain carat size, then consider slightly compromising other diamond qualities. Normally, I would choose lower diamond color or clarity grades but not too low. But even as you head for the big stones, keep in mind that larger carat weights tend to fit only specific settings. 

Make sure you decide on which settings you want first before hunting for diamonds on a carat weight basis. Overall, it is important to consider all the 4Cs before buying a diamond since they’ll all play important roles in determining the beauty of your diamond.

Read also: 51 Ways to Save on Diamond Rings

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