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How to Calculate Diamond Carat Weight

August 8, 2017 - Diamond Articles
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Carat weight is one of the most important factors when looking to sell, buy, or evaluate a diamond. One of the 4 Cs of diamond grading, carat weight is a crucial attribute of your stone. If you do not know the carat weight of your diamond, you may be wondering: how can I calculate diamond carat weight? How do you tell how many carats a diamond is? Read below to learn more about carat weight and how to calculate it, including answers to some of the most commonly asked questions regarding carat weight:

  • What is carat weight?
  • Where does carat weight come from?
  • How is carat weight measured?
  • Does carat weight relate to size?
  • How does carat weight affect the value of my diamond?
  • Can I measure diamond carat weight at home?
  • How can I calculate the carat weight of my diamond?

 

WHAT IS CARAT WEIGHT? 

Carat is a unit of measurement used to weigh diamonds and other stones. Contrary to popular believe, carat weight denotes weight, not size. A single carat is equivalently to 0.2 grams, or about the weight of a raindrop. Carat is the standard unit of measurement across the jewelry and gem industry.

 

WHERE DOES CARAT WEIGHT COME FROM? 

The history of carat weight extends as far back as Ancient times. Early gem traders used carob seeds as units of measurement to weigh their gems, since carob seeds varied little in weight and were light enough to measure differences in small stones. The word “carat” stems from the word carob. It was later realized that carob seeds can vary significantly in weight based on region, and that the carob seed system was not an accurate measuring tool. At the 1907 meeting of the General Conference on Weights and Measures, an official global conference to discuss worldwide physical measurements, the carat was defined as weighing 200mg. In 1913, the carat weight was officially adopted as the unit of measurement for diamonds and other stones in the United States, and it quickly spread to global usage.

what is diamond carat weight

HOW IS CARAT WEIGHT MEASURED? 

Because carats are such a small unit of measurement, and a small discrepancy in carat weight can drastically impact the value of a stone, carat weight is typically measured to the thousandth of a carat and then rounded to the nearest hundredth. Specialized measuring tools are often used to ensure precise, accurate measurements. Carat weight is often abbreviated to “ct” (or “CT”). Sometimes carat weight is denoted as “cw” (or “CW”) or diamond weight, “dw” (or “DW”).

Carat weight refers to the weight of a single stone, whereas total carat weight refers to the weight of all of the stones on an item of jewelry. Total carat weight is often abbreviated as “ctw” (or “CTW”), “tw” (or “TW”), or diamond total weight, “dtw” (or “DTW”).

 

DOES CARAT WEIGHT RELATE TO SIZE? 

Carat weight does not directly correlate to size. Though, typically, the more a diamond weighs, the larger it will appear, this does not tell the whole story. Though a 300-carat stone will certainly be larger in size than a 3-carat stone, there is no precise correlation between carat weight and size. Two diamonds of the same carat weight can have a dramatically different look and size. A 2-carat diamond with a high depth and small diameter may appear much smaller than another 2-carat diamond with low depth and a large diameter. Different shapes of diamonds with the same carat weight will often appear to be drastically different sizes.

 

HOW DOES CARAT WEIGHT AFFECT THE VALUE OF MY DIAMOND? 

The bottom line is that the greater the carat weight, the more a diamond is worth. In 2013, the largest diamond ever sold at auction, a 118-carat gem, was purchased for a whopping $30.6 million. This record-breaking sale is evidence of the high value of large carat weight diamonds.

Carat weight is one of the largest determinants of the value of your diamond. Along with color, cut, and clarity, carat weight is one of the 4 Cs used to assess diamond quality and value. Larger diamonds are much rarer and harder to find than smaller diamonds, and consumers generally desire larger stones over smaller stones. Due to the rarity of larger stones, as carat weight increases, price-per-carat also increases significantly (all other things being equal).

There are some nuances to how carat weight affects value. Many consumers are interested in purchasing a diamond that they can claim is 1 carats, 2 carats, 3 carats, etc. Therefore, a diamond weighing .99 carats will be much less valuable than a 1 carat diamond and a 1.99 carat diamond will be much less valuable than a 2 carat diamond.

But remember that while carat weight can have a significant effect on the value of a diamond, there are still many other attributes that will factor into how a diamond is priced.

large diamond record
CAN I MEASURE DIAMOND CARAT WEIGHT AT HOME? 

The quick answer is that without the proper specialized tools, it can be difficult to get an accurate measurement of your diamond’s carat weight at home. However you can determine the carat weight of your diamond with our free online diamond weight calculator.

 

HOW CAN I CALCULATE THE CARAT WEIGHT OF MY DIAMOND? 

WP Diamonds’ free online carat weight calculator is an easy way to get a rough estimate of the carat weight of your diamond. Using the diamond shape, length, width, and height, WP Diamonds will provide an estimate of your diamond’s carat weight, rounded to the nearest hundredth.

This carat weight estimate can be particularly useful if you are looking to sell your diamond online. WP Diamonds offers a free, secure service for selling your diamonds, designer jewelry, and luxury watches from the comfort of your own home. Simply fill out the online form and provide some basic information about your diamond, including the estimated carat weight, and a member of our team will be back in touch shortly with an initial price valuation. WP Diamonds is a BBB A+ rated company.

Author
Bio: Written by one of our diamond, designer jewelry or luxury watch experts. With over 150 years of combined experience, our experts are able to comment on trends, share industry knowledge and provide diamond, designer jewelry and luxury watch education.

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