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Diamond Carat

What does carat mean in diamonds?

A 'carat' is a unit of measurement used in the diamond industry to specify the weight of a diamond. A carat is equal to 200 milligrams, so a 5-carat stone weighs 1 gram.

Is diamond carat the same as size?

No - people often assume a diamond's size is synonymous with its carat weight, but this isn’t always the case. There are other factors that can affect the size of a diamond.

Visually, different diamond shapes can make diamonds of the same carat size appear larger or smaller. For example, a marquise diamond will always appear larger than an oval diamond, simply because it has a larger surface area.

Similarly, the cut of a diamond can also impact the size of a diamond. Poorly cut diamonds that change in depth or feature a thick girdle often weigh more but appear smaller because their weight sits in the base of the diamond. In turn, there is less surface area on top - so not only does your diamond appear smaller, it will also sparkle less.

What do different carat sizes look like?

As carats aren’t always synonymous with the size of a diamond, it can be hard to visualise the different carat sizes. So, we’ve provided an approximate diamond carat and round diameter chart below.

Diamond carat weight size chart

Want a closer look at our carat sizes? Book an appointment via our homepage or visit us in-store.

How do I choose a diamond carat?

Looking for a diamond engagement ring but don’t know which carat to choose? Our diamond carat guide will ensure you choose the perfect diamond carat weight for your diamond ring!

  1. Choose carat weight to suit the wearer's fingers When buying a diamond ring you should choose a diamond carat weight that suits the wearer's fingers. For example, a larger carat may look very prominent against slender fingers, which isn’t to everyone’s taste.
  2. Consider size vs budget. A larger carat doesn’t necessarily make for a larger diamond – so don’t blow your entire budget on carat weight. Instead, distribute it evenly across all characteristics. After all, a large diamond with poor clarity and colour won’t have the same sparkle as a lower carat, higher quality diamond.
  3. Explore all carat sizes. At Shining Diamonds, customers can choose from a variety of diamond carat weights ranging from 0.25ct to 1.00ct. This is the most popular carat weight range, but if needed, we can also source carat weights larger than 1.00ct.

Select your carat with confidence

Now you understand what carat size means, you can choose your diamond with confidence! However, if you need further assistance, contact our team at Shining Diamonds or visit us at our Hatton Garden or Brighton jewellery store. We also offer finance for all of our diamonds both in-store and online. So don’t hesitate - find your dream diamond today!

The modern carat system began with the carob seed - a seed from a tree that grows in the Mediterranean and has fruit pods that contain multiple seeds. Those very early gem traders used small uniform seeds as counterweights to balance their scales. The modern diamond carat system was adopted by the United States in 1913 and other countries soon followed later. Today, a diamond carat weighs exactly the same in every corner of the world.

What are “magic sizes”? Some weights are known as “magic sizes” - half carat, three-quarter carat and carat. There is little difference visually between a 0.99 carat diamond and one that weighs a full carat. However, the price difference between the two can be quite significant.

We estimate that a 1 carat diamond can cost anything between £6,000 and £10,000. However, the cost of a 1 carat diamond can vary drastically depending on the quality of the other 4Cs. Equally, lab grown diamonds cost less than natural diamonds despite sharing the same chemical and physical properties.