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WHAT IS CARAT?
Carat refers to the weight of a diamond. Diamonds are all weighed in metric carats rather than grams or ounces. This is a standard industry practice around the world.
Diamond is expressed to the hundredth of a carat. Carat weight of less than a carat is expressed in points. So, for example, a 0.75ct diamond will be 75 points. Most jewellers will refer to carat weight in this terminology.
Another way to explain this would be using pounds, 100 pence equals 1 whole pound. Therefore 50pts will be 0.50ct and so on.
HOW TO WORK OUT CARAT WEIGHT?
A common misconception is that it refers to the physical size of a diamond, which is incorrect. The diamond weight does not govern the size of stone.
We always recommend trying a range of carat weight on to determine which will be best for you. This way you will also be able to assess the visible size. For those who can’t come into our store to view diamonds we have the chart below to give you an indication on size.
| Carat Weight | 0.25ct | 0.50ct | 0.75ct | 1ct | 1.50ct | 2ct | 3ct | 4ct | 5ct | Carat Weight | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Round |  |
4mm | 5mm | 5.50mm | 6.50mm | 7.50mm | 8mm | 9.40mm | 10.40mm | 11.20mm | |
| Princess |  |
3.50mm | 4.50mm | 5mm | 5.50mm | 6.80mm | 7.50mm | 8mm | 8.90mm | 9.70mm | |
| Heart |  |
4x4mm | 5x5mm | 6x6mm | 6.50x6.50mm | 7x7mm | 8x8mm | 9x9mm | 10x10mm | 11x11mm | |
| Emerald |  |
4x3mm | 6x4mm | 6.50x4.50mm | 7x5mm | 8x6mm | 8.50x6.50mm | 10x8mm | 11x9mm | 10x10mm | |
| Asscher |  |
3.70mm | 4.40mm | 5mm | 5.80mm | 6.40mm | 7mm | 8.10mm | 9mm | 9.60mm | |
| Marquise |  |
5x3mm | 8x4mm | 9x4.50mm | 10x4.75mm | 11x5mm | 12x6mm | 14x7mm | 15x7mm | 16x8mm | |
| Radiant |  |
3.50x3mm | 5x4.50mm | 5.50x5mm | 6x5.50mm | 7x6mm | 7.50x7mm | 8.50x7.50mm | 9.50x8.50mm | 10x9mm | |
| Cushion |  |
4x3.50mm | 5x4.50mm | 6x5mm | 6.50x5.50mm | 7.50x6.50mm | 8x7mm | 9x8mm | 10x8.50mm | 10x9.50mm | |
| Oval |  |
5x3mm | 6x4mm | 7x5mm | 7.50x5.50mm | 8.50x6.50mm | 9x7mm | 10x8mm | 11x9mm | 12x10mm | |
| Pear |  |
4x2mm | 6x4mm | 7x5mm | 8x5mm | 9x6mm | 10x7mm | 12x8mm | 14x9mm | 15x10mm | |
HOW TO GET THE BEST SIZE FOR CARAT?
The characteristic that makes the most difference in the visual appearance of a diamond is the cut. You will often have two diamonds of the same carat weight that are different in visual size depending on their cut.
For example, a diamond that is graded as a poor cut would have a small visual appearance, where as a very good or excellent cut would be a lot closer to the visual look you should expect. If a diamond is deeper, then it will have a smaller diameter and if it is shallow then it will have a bigger spread.
For example, you can get a 1.00ct Round diamond graded as ‘fair’ or ‘poor’ cut that measures 5.9mm. You can then have a round diamond graded as an excellent cut which measures 6.6mm approximately.
You can visit our ‘cut’ education section to get more in depth information on this. If you’re still unsure as to which carat size is for you contact us on [email protected] or 0345 222 5009.
