Common weights for Round Brilliant diamonds.
| Diameter (mm) | Approx Weight |
|---|---|
| 4.1 mm | 0.25 ct |
| 5.2 mm | 0.50 ct |
| 5.8 mm | 0.75 ct |
| 6.5 mm | 1.00 ct |
| 7.4 mm | 1.50 ct |
| 8.1 mm | 2.00 ct |
If you cannot remove the diamond from its setting, you can estimate carat weight by measuring the diameter (length) and depth in millimeters.
Formula: Length x Width x Depth x S.G. Factor.
This calculator uses standard specific gravity factors for different shapes to give you a precise estimate.