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Diamond Size Chart 

Diamond Carat Size Chart and Interactive Diamond Size Guide 

The following Diamond size chart provides a very effective way to view both Diamond sizes and shapes on the finger. Using the menus, select your desired Diamond shape and carat weight. Use our Diamond mm size chart to find out approximate mm sizes for popular Diamond shapes. This handy reference tool gives all of the Diamond carat weight and mm. sizes for all of the Diamond shapes in an easy to use tool, perfect for reference. The following size chart includes sizes of Round, Princess, Oval, Emerald-cut, Pear-shape, Heart-shaped, Cushion-cut, Marquise, Asscher, Princess-cut and Radiant-cut Diamonds.  

Diamond size instruments

Please remember we have Diamond size instruments, such as the measurement gauge, available in our shop section. Gauges are very handy for establishing the exact measurement of your Diamond, used by jewellers and Diamond merchants Worldwide. 

Diamond Size Conversion Chart

Use the following Diamond size conversion chart to relate mm Diamond size to carat weight. This handy conversion chart helps determine the size of most popular Diamond shapes. 

Notes on diamond mm size

Many Diamonds size charts typically vary according to the measurements provided. Diamond sizes vary depending on how the Diamond is cut. The proportions differ depending on the make of the stone. The visible size of a Diamond is often referred to as the spread of the stone. For consistency, we prefer to demonstrate realistic Diamond sizes, typical for well-proportioned Diamonds.

What is the smallest size available for Diamonds?

Diamonds can be sourced in sizes below 1mm. Would you believe Diamonds are fully cut in such sizes? The smallest sizes are typically Round Brilliant cut Diamonds. Small fully cut round Diamonds are often referred to as "Stars" up to and including 1.7mm (approx. 0.02cts each.) View our additional information on where to buy small diamonds within our knowledge base. 

Coloured Gemstone Sizes

Many coloured gemstones weight differently from diamonds. We work with a variety of precious and semi-precious gemstones. As a result, we are happy to give guidance on carat weights and mm. sizes for a variety of gemstones including Sapphire, Ruby, Tanzanite, Aquamarine, Topaz to name just a few examples. 

Important! - consider carat weight and size when buying Diamonds.

When you purchase a Diamond, consider both carat weight and physical size along with other factors. Let us explain why this is important. 

John, purchased a Diamond online. The Diamond weighed 0.60cts and seemed remarkable value. It was GIA certified which provided even greater reassurance. If John had considered the size of the Diamond he would have realised the stone was cut a little deeply. It only measured 5.1mm. If he'd purchased a Diamond 0.55cts with a better cut, he would benefit from a superior Diamond, with greater brilliance. 

Handy rules of thumb for Diamond sizes

Many Diamond shapes weigh heavier than Round Brilliant cut Diamonds. There are no tricks to learning Diamond sizes. A Diamond expert learns sizes over many years through experience and learning. Most people rely on reference material like the chart and application above.

Diamond size knowledge is essential when providing information to others. Such guidance forms part of our service at Serendipity Diamonds. If you are searching for any size, shape, colour or clarity of Diamond then contact us for help. 

Interactive Diamond Size Chart - Diamond sizes on the hand

Use our interactive diamond size chart to get a better idea of diamond sizes across the different diamond shapes. This easy-to-use size chart allows you to choose your skin tone, diamond shape and carat weight. In addition, each diamond choice is shown with the respective mm. sizes for your diamond. Please note that the interactive size chart is only available on desktop computers and not mobile. If you are not seeing this chart, then jump onto a desktop computer to look at the different diamond sizes on the hand. 

Expressing popular Diamond sizes in terms of carat weight.

How heavy is a 1mm Round Brilliant cut Diamond? 

A 1mm Round Diamond is approximately 0.005 carats in weight. 

How heavy is a 1.5mm Round Brilliant cut Diamond? 

A 1.5mm Round Diamond is approximately 0.015 carats in weight. 

How heavy is a 2mm Round Brilliant cut Diamond? 

A 2mm Round Diamond is approximately 0.03 carats in weight. 

How heavy is a 3mm Round Brilliant cut Diamond? 

A 3mm Round Diamond is approximately 0.10 carats in weight. 

How heavy is a 4mm Round Brilliant cut Diamond? 

A 4mm Round Diamond is approximately 0.25 carats in weight. 

How heavy is a 5mm Round Brilliant cut Diamond? 

A 5mm Round Diamond is approximately 0.50 carats in weight. 

How heavy is a 6mm Round Brilliant cut Diamond? 

A 6mm Round Diamond is approximately 0.80 carats in weight. 

How heavy is a 6.5mm Round Brilliant cut Diamond? 

A 6.5mm Round Diamond is approximately 1 carats in weight. 

How heavy is a 7mm Round Brilliant cut Diamond? 

A 7mm Round Diamond is approximately 1.25 carats in weight.