Carat to MM Conversion
Carat to MM Conversion
A guide to compare a diamond’s carat weight to its approximate top dimensions.
In the case of brilliant cut diamonds, the millimetre value refers to the stone’s diameter. For princess cut diamonds, the millimetre value means that dimension square. Please note this is only a rough guide as the weight of the stone will vary depending upon its depth.
| BRILLIANT CUT | PRINCESS CUT | MARQUISE CUT | OVAL CUT | PEAR CUT | EMERALD CUT |
|---|---|---|---|---|---|
| 0.06-0.08cts = 2.5mm | 0.06-0.08cts = 2.1-2.2mm | 0.07ct = 4X2mm | 0.15-0.18ct = 4X3mm | 0.15-0.18ct = 4.5X3mm | 0.25ct = 4X3mm |
| 0.10-0.12cts = 3mm | 0.10-0.12cts = 2.5-2.7mm | 0.15ct = 5X2mm | 0.25ct = 5X3mm | 0.25ct = 5X3.5mm | 0.35ct = 5X3mm |
| 0.16-0.18cts = 3.5mm | 0.16-0.18cts = 3mm | 0.20ct = 5X3mm | 0.40ct = 5X4mm | 0.35ct = 5.75X4mm | 0.40ct = 5X3.5mm |
| 0.20-0.22cts = 3.8mm | 0.20-0.22cts = 3.2-3.3mm | 0.25ct = 6X3mm | 0.50ct = 6X4.5mm | 0.40ct = 6X4mm | 0.50ct = 5X4mm |
| 0.24-0.26cts = 4mm | 0.24-0.26cts = 3.4-3.5mm | 0.35ct = 6.5X3.5mm | 0.65ct = 6.5X4.5mm | 0.50ct = 6.5X4.5mm | 0.60ct = 6X3mm |
| 0.27-0.29cts = 4.2mm | 0.27-0.29cts = 3.5mm | 0.35ct = 7X3mm | 0.75ct = 7X5mm | 0.75ct = 7X5mm | 0.70ct = 6X4mm |
| 0.30-0.35cts = 4.5mm | 0.30-0.35cts = 3.8-3.9mm | 0.40ct = 6.5X4mm | 1.00ct = 7.5X5.5mm | 1.00ct = 8X5mm | 0.80ct = 6.5X4.5mm |
| 0.36-0.38cts = 4.6mm | 0.36-0.38cts = 3.8-3.9mm | 0.50ct = 7X4.5mm | 1.25ct = 8X6mm | 1.50ct = 9X6mm | 0.95ct = 7X4mm |
| 0.39-0.43cts = 4.7-4.8mm | 0.39-0.43cts = 3.9-4.1mm | 0.70ct = 8X5mm | 1.50ct = 8.5X6.5mm | 1.00ct = 7X5mm | |
| 0.44-0.47cts = 4.8-4.9mm | 0.44-0.47cts = 4.1-4.3mm | 0.70ct = 9X4mm | 1.75ct = 9X6mm | 1.25ct = 7.5X5.5mm | |
| Â 0.48-0.52cts = 5mm | Â 0.48-0.52cts = 4.3-4.5mm | Â 0.75ct = 9X4.5mm | Â 2.00ct = 9X6mm | Â 1.50ct = 8X5mm | |
| Â 0.53-0.59ctsct = 5.2mm | Â 0.53-0.59ctsct = 4.6mm | 0.80ct = 9X5mm | Â 2.00ct = 8.5X6.5mm | ||
| Â 0.60-0.62cts = 5.3-5.4mm | Â 0.60-0.62cts = 4.7mm | Â 1.00ct = 9X6mm | Â 2.25ct = 9X6mm | ||
| Â 0.63-0.68ctsct = 5.5-5.6mm | Â 0.63-0.68ctsct = 4.8mm | Â 2.50ct = 9X7mm | |||
| Â 0.69-0.74cts = 5.6-5.8mm | Â 0.69-0.74cts = 4.8-4.9mm | ||||
| Â 0.75-0.80cts = 5.9-6mm | Â 0.75-0.80cts = 4.9-5mm | ||||
| Â 0.90-0.92cts = 6.2-6.3mm | Â 0.90-0.92cts = 5.1-5.2mm | ||||
| Â 0.93cts-0.99cts = 6.3-6.4mm | Â 0.93cts-0.99cts = 5.2-5.3mm | ||||
| 1.0cts-1.05cts = 6.4-6.5mm | 1.0cts-1.05cts = 5.3-5.5mm | ||||
| Approx 1.1cts = 6.6mm | Approx 1.1cts = 5.8mm | ||||
| Approx 1.25cts = 6.8-6.9mm | Approx 1.25cts = 6mm | ||||
| Approx 1.3cts = 7mm | Approx 1.3cts = 6.1mm | ||||
| Approx 1.4cts = 7.2-7.3mm | Approx 1.4cts = 6.2mm | ||||
| Approx 1.5cts = 7.5mm | Approx 1.5cts = 6.4mm | ||||
| Approx 1.75cts = 7.7-7.8mm | Approx 1.75cts = 6.6-6.8mm | ||||
| Approx 2cts = 8-8.2mm | Approx 2cts = 7mm |
