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The Diamond Size Calculator helps individuals estimate the physical dimensions of a diamond based on its carat weight. This tool is useful for jewelers, buyers, and enthusiasts who want to understand how carat weight translates into actual size. It simplifies the process of determining the millimeter diameter or measurements of a diamond, depending on its cut and shape.
Formula

where:
- Carat Weight is the total weight of the diamond in carats.
- Standard Size Factor depends on the diamond shape (e.g., 6.5 for round diamonds).
Approximate Diamond Size for Different Carats (Round Cut):
Carat Weight | Approximate Size (mm) |
---|---|
0.25 | 4.1 |
0.50 | 5.1 |
1.00 | 6.5 |
2.00 | 8.2 |
3.00 | 9.3 |
Diamond Size Reference Table
This table provides estimated diamond dimensions for various shapes and weights.
Diamond Shape | 0.50 Carat (mm) | 1.00 Carat (mm) | 2.00 Carats (mm) |
Round | 5.1 | 6.5 | 8.2 |
Oval | 5.3 x 3.8 | 7.7 x 5.7 | 10.5 x 7.0 |
Emerald | 5.0 x 3.5 | 7.0 x 5.0 | 9.0 x 6.5 |
Marquise | 7.5 x 3.5 | 10.5 x 5.0 | 14.0 x 7.0 |
Cushion | 5.0 x 5.0 | 6.5 x 6.5 | 8.5 x 8.5 |
These values serve as general guidelines for estimating diamond sizes based on carat weight.
Example of Diamond Size Calculator
A buyer is considering purchasing a 1.5-carat round diamond and wants to estimate its size.
Using the formula:
Diamond Size (mm) = (1.5)^(1/3) × 6.5
By solving for the value, the estimated diamond size is approximately 7.3 mm in diameter.
This helps the buyer visualize the diamond size before making a purchase.
Most Common FAQs
Carat weight influences the overall dimensions of a diamond, but shape and cut also play a role in determining its actual visual appearance.
No, different diamond shapes and cuts distribute weight differently, affecting their perceived size and face-up appearance.
Diamonds with shallower cuts and larger surface areas may look bigger, whereas deeper cuts may appear smaller despite having the same carat weight.