Carat Weight

Cut may rule the diamond parameters, but carat weight is just as important! But before we dig deeper, please note that carat refers to the weight and not the size of a diamond. Although, in general, the size of a diamond increases together with its weight.

Now, the word carat is actually derived from the word “Carob” which is a specific bean of the locust tree. Since Carob seeds were believed to be very even in their weight distribution, they were used to measure fine jewellery in the past. Diamonds are measured in carat and 1 carat is exactly 0.2 grams. This, however, is a factual inaccuracy, but it still goes to show that myths can survive for a very long time.

Given today’s standards, it seems like an unreliable method to measure the weight of a diamond. Still, the word carat lived on!

Carob beansAnd oh, one more thing! Diamond carat is for weight and gold karat is for measuring gold purity, so don't get the two terms mixed up.

Gold fineness expressed in karats comes from carats and grains of gold in the ancient roman solidus coin. One solidus coin used to be 24 carats which was preserved up to this day.

Is carat weight the most important factor when buying a diamond?

No, and I hope you already know that!

Ultimately, a diamond is all about looks, brilliance, fire, and scintillation. All these characteristics are determined by the diamond cut. And only a diamond with Excellent cut proportions will provide you with the maximum brilliance that you should initially be looking for.

5 carats rings

However, if you have a diamond with great cut, more carat weight will make the facets of the diamond appear larger which will also return more light and sparkle to the viewer’s eye.

But still, it should be your main priority to make sure that you get the best possible cut, so that you can then adjust the carat weight accordingly.

The reality is, far too many people are focused on the carat weight because this is the first question that you will likely be asked by relatives and friends. For them, it is a matter of prestige to be able to say that one’s diamond has at least 1 carat in weight. So, in order to make the diamond affordable, many people compromise on the cut. I would advise you not do that!

Why exactly is the cut more important than the carat weight?

Let me answer this question by showing you two outlines of two different diamonds. Both diamonds are exactly one carat in weight.

The diamond on the left side has a pavilion depth of 66.4 %. Thus, there's a lot of hidden weight in it and it only measures 6.2 mm in diameter. While the one on the right has a depth of 61.7 % giving it optimal depth according to super optimal diamond cut proportions!

impact of the depth on the diameter

This makes the diamond appear 6.5 mm in diameter, producing a very noticeable difference as with every mm more in diameter, the surface of the diamond increases exponentially (you might remember the formula π * r² back from school). In addition, a larger surface means more light being returned to the viewer’s eye and thus, a larger amount of sparkle and scintillation is produced!

So, by choosing a better cut, your diamond appears larger and seems to have more carat weight. You might wonder why there are people out there who pay more attention to carat weight than the cut grade! Sadly, these people are mostly misinformed or they don’t really care about the beauty of the diamond, but just want to be able to say that they bought a gem with such and such carat weight.

How does an increase in carat weight affect a diamond?

The carat weight impacts both the price and size. In fact, a diamond with two carat does not appear twice as large as a diamond with one carat.

round diamonds carat size chart

If you want to have a general idea of what the diamond with your specific carat weight will look like mounted onto a ring setting, you can use the James Allen carat size simulator.

James Allen Carat Size Simulator

Furthermore, the price per carat increases exponentially because any finished diamond is yielded from only one piece of rough. To obtain a bigger diamond, the rough will also have to be bigger.

As large rough diamonds occur far rarely in nature than its smaller counterparts, the prices increase accordingly. This is why 1 carat diamond rings are surprisingly more expensive than, for instance, 0.9ct diamond rings.

Now, here's a table I've created with round cut diamonds from James Allen with the same cut, color, clarity except carat weight. As you can see, the price increases exponentially:

All other things being equal the price of a diamond increases exponentially the more carat a diamond has

All other things being equal, the price of a diamond increases with more carat weight it has.

Here’s another example showing the price difference between a 2 carats and 3 carats:





This perfectly exhibits how the weight increase doesn’t really equate to exact price increase. In ideal terms, given the same 3Cs, if the 2 carat gem is worth $24,130, then a 4 carat gem would more or less be $50,000.

But as you can see in the example above, the price of 3 carats surpasses the estimated value. By the same token, this leads us to question diamonds in different shapes.

Is there a price difference among diamond shapes with the same carat weight?

Yes, there is! As a matter of fact, some might think that the price difference is dependent on shape popularity only, which is partially true, but a particular shape is more in demand because ultimately, it produces optimal brilliance.

We already know that the ideal cut is behind this, but you should also know that carat weight is the dark horse behind the price of fancy shaped diamonds.

This is because all the other shapes aside from the round cut conserve more weight which means less diamond rough is wasted during the cutting process. The round cut is the most expensive because cutters would have to remove the most amount of rough compared to other shapes.

This will give you a better visual:

    • Cushion cut diamond and its natural rough

      Cushion Cut Diamond and Its Natural Rough

    • round cut and diamond rough

      More rough wasted when cut as a round diamond.

Even though two diamonds have the same carat weight and quality, you can save 25% with fancy shaped diamonds as round cuts’ popularity demands higher manufacturing costs.

To show you how different shapes affect the price, I’ve compiled James Allen fancy shaped diamonds with the same 4CS: 1 carat, G-VS2, Excellent Cut

prices of different shapes in 1 carat

Fancy shapes are cheaper by $1,200 to $3,200 compared to round cuts.

Speaking of getting the biggest bang for your buck, have you heard of the magical carat mark?

The Carat Weight That Will Save You Money

Remember when I mentioned how some people are obsessed with a specific carat weight? When asked about the carat size (which is always!), they want to be able to announce that their diamond is 1 carat because it just sounds so good! But with the sought after number, comes a steeper price.

Being a favorite, cutters will try to produce more popular sizes even if that means bearing slightly lower 3Cs. If you try searching for diamonds with 0.99 carat, you won’t see as many as 1 carats.

Both diamonds bear the cheapest G color, VS2 clarity and Excellent Cut in their respective carat sizes – 0.9ct and 1ct:





Can you see how expensive the 1 carat diamond can get? The difference is almost $2,000!

Obviously, diamond prices escalate at certain weight points. And diamonds become more affordable if they're marked just slightly under the popular weight!

And honestly, even if you look closer, you’ll find it difficult to distinguish which one’s bigger. Since there’s not much difference in weight, a diamond at 0.9ct and a 1 carat may have the same diameter. Thus, both gems will appear as the same carat size especially when viewed from above.

However, more people are getting informed that the carat sizes below the 1 carat mark are way cheaper. In fact, I talked about how 0.9ct has become the average engagement ring size in 2016. For 2017, it will probably be the same since online buyers are given better tools for smarter shopping.

New Age Diamond Shopping

VVS1 clarity diamond

I’m talking about our community of diamond enthusiasts who are passionate in sharing diamond knowledge for beginners. And of course, reputable online vendors that make diamond shopping a leap forward in today’s technology.

James Allen is currently on top of my list because they offer high definition diamond displays and advanced filter tools that make diamond hunting more convenient especially for first-time seekers.

Click Here To Check out James Allen Now

What’s the Takeaway?

At the end of the day, your preference is all that matters. You could either be one of these kinds: People who are psychologically affected by the smooth carat size – 1. That even if what they have is a 0.99 carat diamond ring, they wouldn’t feel satisfied unless they’re wearing the magical number.

And those who find even the smallest of ways to get the maximum value for their money. Thus, opting for a 0.9 carat diamond.

My advice is to make sure you have the best cut first before deciding on the carat weight. You’ll be surprised how majestic a diamond will seem with an excellent cut compared to a bigger gem with a poor cut. But don’t just take my word for it. See for yourself!

Discover more about diamond color on the next page…

Read Next: Diamond Color



Sebastian Naturski loves to write about diamonds and share his knowledge with his readers.
When he is not working on his website he is studying law at Humboldt University of Berlin.
He has taken part in several international law competitions and likes to broaden his horizons.
His other big passion are languages. He is fluent in German, English, Polish and Japanese and got basic skills in French and Spanish as well.


  1. Could you give some advice on which size increase increments you think are significant?

    You wrote: Every mm more in diameter, the surface of the diamond increases exponentially (you might remember the formula π * r² back from school).

    So, for example, do you think a 0.25mm increase is significant enough to warrant paying more? Equally, what about 0.5, 0.75 and 1mm.

    When does it make sense to pay more?

    • Hi K,

      There’s a rule of thumb that 0.2 is considered visible to a normal person. Although some people notice a difference between two diamonds that’s only .01mm – .04mm apart if they’re compared next to each other. It’s a different story when these diamonds are set on a ring and it becomes more difficult as the size increases. So it actually depends.

      But if we’re going with the 0.2 rule, then yes, the 0.25mm increase will be significant. Same with 0.50, 0.75, and 1mm. It’s worth paying for once you’ve made sure you have the best cut and your diamond is eye clean.

  2. Hi Sebastian,
    I’ve learned so much from your website. Thank you! I’m looking between the following 2 diamonds for an engagement ring. Which one do you think is the better diamond and why do you think so? Thank you for your help!

  3. Hi Sebastian
    I would like to know if I would like to have a rose gold colour setting with a J colour and VVS2 round cut diamond, is there an optimum carat value of the diamond for the color above? For example, if the diamond gets too big, it might become too obvious that the diamond is a bit yellowish. And does the type of setting have effect on this too? For example, if the setting you have is a pave setting with lots of small H color diamonds, would the J color affect the aesthetic look of the ring? Thanks heaps in advance.

    • Hi Gibs,

      Even a K color can go up to 2.5 carats in this post. And you can go as big as 5 carats, as long as it looks neat to you. The color will only be evident if you place your ring next to a diamond with a higher color grade, which, of course, won’t happen everyday. For pave settings and side stones, I would recommend the same color or a slightly darker color to highlight the higher color grade of the center diamond. Hope that helps, cheers!

  4. Hi Sebastian.
    I wanted to buy a diamond with a max budget of around US$20,000.
    I know it needs a GIA or IGI cert to be investment grade.
    I have read all your 4 c’s comments, and I wanted your thoughts.

    Whats the best value INVESTMENT grade I should look for.

    I know Not to buy better than a VS1 for clarity.

    Color is to go for F or G, as higher is just a waste of money and you cant see difference in naked eye anyway.
    Cut must be excellent for it to be investment grade I know that.

    And caret anything above 1ct is investment grade right?

    Is this roughly what I should be looking for when buying a potential investment grade diamond to get the most bang for my buck, but for the gem to still be considered investment grade and for it to be easier to sell?
    thanks a lot.

    • Hi Jake,

      That’s right! The 4Cs you mentioned are spot on. Investment-grade diamonds with the highest potential for appreciating weighs around .75 carats or better, so 1 carat is definitely a good investment.

      Just remember to separate your diamond from the setting because knowing the value of the gem alone will give you a better understanding of how your initial investment truly stands.

      Also, you might want to reconsider your budget because you an actually find more affordable gems with the same qualities or even better online. Take a look at this example:

      Goodluck! 🙂

  5. Thanks for the post.
    I actually wanted to take a Very Good cut so that I can afford a a diamond with above 1 carat.
    But now I think I will rather try to save money on color and if possible on clarity.

  6. Hey Sebastian
    great information, i am in the process of looking for the right ring for my fiance. Your website is really helpful so i can choose the right one.

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