Diamond Size Chart of Round Cut Lab Diamonds
This round cut lab diamond size chart provides a guide for understanding diameter sizes of diamonds in millimeters and their carat weight. The carat weight can vary slightly based on the cut and proportions of the diamond, but this gives a reliable estimate for the typical carat sizes based on the diameter.
Round Cut Diamond Size Chart (0.8 – 5.0 mm)
| Size(mm) | Carat Weight(ct) |
|---|---|
| 0.80 | 0.0025 |
| 1.00 | 0.005 |
| 1.20 | 0.009 |
| 1.30 | 0.01 |
| 1.50 | 0.015 |
| 1.75 | 0.02 |
| 1.80 | 0.025 |
| 2.00 | 0.03 |
| 2.20 | 0.04 |
| 2.50 | 0.06 |
| 2.75 | 0.08 |
| 3.00 | 0.1 |
| 3.25 | 0.14 |
| 3.50 | 0.17 |
| 3.75 | 0.21 |
| 4.00 | 0.25 |
| 4.25 | 0.28 |
| 4.50 | 0.36 |
| 4.75 | 0.44 |
| 5.00 | 0.5 |
Round Cut Diamond Size Chart (5.5 – 11.0 mm)
| Size(mm) | Carat Weight(ct) |
|---|---|
| 5.50 | 0.66 |
| 5.75 | 0.75 |
| 6.00 | 0.84 |
| 6.50 | 1 |
| 6.80 | 1.25 |
| 7.00 | 1.3 |
| 7.30 | 1.5 |
| 7.50 | 1.67 |
| 7.75 | 1.75 |
| 8.00 | 2 |
| 8.50 | 2.43 |
| 8.70 | 2.5 |
| 9.00 | 2.75 |
| 9.10 | 3 |
| 9.50 | 3.35 |
| 9.75 | 3.5 |
| 10.00 | 3.87 |
| 10.75 | 4 |
| 11.00 | 4.41 |
| 10.75 | 4.5 |
How to Read the Size Chart
Millimeter Size (mm): The diameter of the diamond measured in millimeters.
Carat Weight: The weight of the diamond in carats, which is related to the size of the diamond but also influenced by the diamond’s cut and shape.
This size chart applies to round cut lab grown diamonds. Shop our wholesale round brilliant loose stones or read about CVD vs HPHT diamonds.