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Diamonds Factory
2nd Floor,
54 Hatton Garden
London
EC1N 8HN
Mon - Fri : 09:30am - 05:30pm
Saturday : 09:30am - 05:30pm
Sunday : 10:00am - 04:00pm
Diamonds Factory
Shop 12
The Big Peg
Access via Warstone Lane
Birmingham B18 6NF
Mon - Fri : 09:00am - 05:00pm
Saturday : 09:00am - 05:00pm
Sunday : 10:00am - 04:00pm
Please visit our partners 'Austen & Blake'
Jewellers at
17 King Street,
Manchester,
M2 6AW
Mon - Fri : 09:30am - 05:30pm
Saturday : 10:00am - 05:30pm
Sunday : 10:30am - 04:30pm
Please visit our partners 'Austen & Blake'
Jewellers at
Unit 9, County Arcade
Victoria Quarter
Leeds, LS1 6BW
Monday - Friday : 10:00am - 05:30pm
Saturday : 09:30am - 5:30pm
Sunday : 11:00am - 4.30pm
Diamonds Factory
Unit 301, Third Floor
Merchants Court,
2-12 Lord Street,
Liverpool L2 1TS
Mon - Fri : 09:30am - 05:30pm
Saturday : 10:00am - 05:30pm
Sunday : Closed

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Diamond Carat

Diamond carat refers to the weight of the diamond rather than the actual size. This means that the larger the carat, the heavier the diamond will be. One carat is equal to 0.2 grams and one diamond carat is divided into 100 points, meaning that 0.25 of a carat is 25 points or ¼ carat.

It is important to consider the carat and cut together when making a purchase. A larger carat diamond with a poor cut grade can appear smaller than a diamond of the same size with a higher cut grade.

Top Tips

To help you choose the perfect diamond carat, we have collated a few top tips


It is a good idea to consider the length and width of the ring finger, for example, a diamond will appear larger on longer and slimmer fingers when compared to shorter and wider fingers. Those with shorter fingers may wish to consider diamond shapes which elongate their appearance such as the marquise or pear.
Another important factor to consider is the setting style, as diamonds set in a delicate or slender setting tend to appear larger than those set in a thicker, more solid setting.
For those on a slightly tighter budget or looking for value for money, a top tip is to look for diamonds which fall just under popular full carat weights - for example, 0.40, 0.90 or 1.75. As these fall just shy of the most sought-after diamond carats, they are often sold at a preferable rate. For example, a 0.90-carat diamond will typically cost less than a 1.00-carat and visually it is difficult to distinguish between the two in size.
You may wish to consider the diamond shape as some shapes can make smaller carats look larger. For example, the marquise and pear shape can appear larger due to its elongated cut.
 

Diamond Carat Size Chart

CT MM
0.25 4
0.50 5.2
0.75 5.8
1.00 6.5
1.25 7.0
1.50 7.2
2.00 8.0
3.00 9.20

Notes

  • Carat is measurement of WEIGHT, not SIZE and the overall diameter (mm) could differe slighter larger or smaller even through carat weight is correct.
  • Image not to scale. Diamond pictures are shown for comparison purpose only. Actual size can very depending your screen resolutions, monitor size etc.
CT MM
0.25 3.5x3.5
0.50 4.25x4.25
0.75 4.75x4.75
1.00 5.5x5.5
1.25 5.80x5.80
1.50 6.25x6.25
2.00 7x7
3.00 7.80x7.80

Notes

  • Carat is measurement of WEIGHT, not SIZE and the overall diameter (mm) could differe slighter larger or smaller even through carat weight is correct.
  • Image not to scale. Diamond pictures are shown for comparison purpose only. Actual size can very depending your screen resolutions, monitor size etc.
CT MM
0.25 6.2x3.3
0.50 7.5x4.2
0.75 8.3x4.7
1.00 9.2x5.2
1.25 10.00x5.60
1.50 10.7x 5.9
2.00 12x6.5
3.00 14.50x7.00

All diamonds are all divisible by the method outlined above. Some very rare diamonds can weigh 100 carats or more and be worth many millions of pounds.

Notes

  • Carat is measurement of WEIGHT, not SIZE and the overall diameter (mm) could differe slighter larger or smaller even through carat weight is correct.
  • Image not to scale. Diamond pictures are shown for comparison purpose only. Actual size can very depending your screen resolutions, monitor size etc.
CT MM
0.25 4.2x3.2
0.50 5.3x3.8
0.75 6.3x4.4
1.00 6.6x4.8
1.25 6.80x5.10
1.50 7.5x5.5
2.00 8.5x6.3
3.00 9.60x6.80

All diamonds are all divisible by the method outlined above. Some very rare diamonds can weigh 100 carats or more and be worth many millions of pounds.

Notes

  • Carat is measurement of WEIGHT, not SIZE and the overall diameter (mm) could differe slighter larger or smaller even through carat weight is correct.
  • Image not to scale. Diamond pictures are shown for comparison purpose only. Actual size can very depending your screen resolutions, monitor size etc.
CT MM
0.25 5.5x3.6
0.50 6.5x4.6
0.75 7.6x5
1.00 8.3x5.2
1.25 9.50x6.10
1.50 9.5x6.2
2.00 10.5x7
3.00 12.00x8.60

All diamonds are all divisible by the method outlined above. Some very rare diamonds can weigh 100 carats or more and be worth many millions of pounds.

Notes

  • Carat is measurement of WEIGHT, not SIZE and the overall diameter (mm) could differe slighter larger or smaller even through carat weight is correct.
  • Image not to scale. Diamond pictures are shown for comparison purpose only. Actual size can very depending your screen resolutions, monitor size etc.
CT MM
0.25 3.8x4.2
0.50 4.7x5.3
0.75 5.9x6.5
1.00 6.3x7
1.25 6.70x7.60
1.50 7.6x8.5
2.00 8x8.8
3.00 8.20x9.85

All diamonds are all divisible by the method outlined above. Some very rare diamonds can weigh 100 carats or more and be worth many millions of pounds.

Notes

  • Carat is measurement of WEIGHT, not SIZE and the overall diameter (mm) could differe slighter larger or smaller even through carat weight is correct.
  • Image not to scale. Diamond pictures are shown for comparison purpose only. Actual size can very depending your screen resolutions, monitor size etc.
CT MM
0.25 5x3.7
0.50 6.1x4.5
0.75 7.1x5.2
1.00 7.7x5.8
1.25 8.30x5.80
1.50 8.6x 6.6
2.00 9.6x6.6
3.00 11.20x8.00

All diamonds are all divisible by the method outlined above. Some very rare diamonds can weigh 100 carats or more and be worth many millions of pounds.

Notes

  • Carat is measurement of WEIGHT, not SIZE and the overall diameter (mm) could differe slighter larger or smaller even through carat weight is correct.
  • Image not to scale. Diamond pictures are shown for comparison purpose only. Actual size can very depending your screen resolutions, monitor size etc.
CT MM
0.25 4.2x3.2
0.50 5.3x3.8
0.75 6.3x4.4
1.00 6.6x4.8
1.25 6.80x5.10
1.50 7.5x5.5
2.00 8.5x6.3
3.00 9.60x6.80

All diamonds are all divisible by the method outlined above. Some very rare diamonds can weigh 100 carats or more and be worth many millions of pounds.

Notes

  • Carat is measurement of WEIGHT, not SIZE and the overall diameter (mm) could differe slighter larger or smaller even through carat weight is correct.
  • Image not to scale. Diamond pictures are shown for comparison purpose only. Actual size can very depending your screen resolutions, monitor size etc.
CT MM
0.25 3.5x3.5
0.50 5.3x3.8
0.75 4.75x4.75
1.00 5.5x5.5
1.25 5.80x5.80
1.50 6.25x 6.25
2.00 7x7
3.00 7.80x7.80

All diamonds are all divisible by the method outlined above. Some very rare diamonds can weigh 100 carats or more and be worth many millions of pounds.

Notes

  • Carat is measurement of WEIGHT, not SIZE and the overall diameter (mm) could differe slighter larger or smaller even through carat weight is correct.
  • Image not to scale. Diamond pictures are shown for comparison purpose only. Actual size can very depending your screen resolutions, monitor size etc.
CT MM
0.25 3.5x3.5
0.50 4.25x 4.25
0.75 4.75x4.75
1.00 5.5x5.5
1.25 5.80x5.80
1.50 6.25x 6.25
2.00 7x7
3.00 7.80x7.80

All diamonds are all divisible by the method outlined above. Some very rare diamonds can weigh 100 carats or more and be worth many millions of pounds.

Notes

  • Carat is measurement of WEIGHT, not SIZE and the overall diameter (mm) could differe slighter larger or smaller even through carat weight is correct.
  • Image not to scale. Diamond pictures are shown for comparison purpose only. Actual size can very depending your screen resolutions, monitor size etc.

Get In Touch

If you'd like to talk to an expert gemologist or a member of our friendly Customer Care Team about diamond carats, please get in touch on 0800 072 1170 0800 072 1170 or enter into a Live Chat as you prefer.