The Diamond Cut Score (Length to Width Ratio) Calculator helps gemologists, jewelers, and buyers evaluate the shape and proportion of a diamond based on its dimensions. The length-to-width ratio is a key factor in assessing the visual appeal and desirability of different diamond cuts. By determining this ratio, users can compare diamonds to ideal proportions for various shapes to ensure they meet aesthetic and quality standards.
Formula
The length-to-width ratio is calculated using the following formula:
Length to Width Ratio = (Diamond Length in mm) / (Diamond Width in mm)
where:
- Length is the longest dimension of the diamond, typically measured in millimeters.
- Width is the shorter dimension perpendicular to the length, measured in millimeters.
Ideal Length-to-Width Ratios for Diamond Shapes
The following table provides ideal length-to-width ratio ranges for popular diamond shapes:
| Diamond Shape | Ideal Length-to-Width Ratio |
|---|---|
| Round Cut | 1.00 – 1.02 (Perfectly Round) |
| Oval Cut | 1.35 – 1.50 |
| Emerald Cut | 1.30 – 1.50 |
| Marquise Cut | 1.85 – 2.10 |
| Cushion Cut | 1.00 – 1.20 (Square to Slightly Rectangular) |
| Radiant Cut | 1.00 – 1.35 |
These ratios help buyers and jewelers determine whether a diamond’s proportions align with industry standards.
Example
A buyer is considering an oval diamond with a length of 8.1 mm and a width of 5.4 mm. Using the formula:
Length to Width Ratio = (8.1 mm) / (5.4 mm)
= 1.50
Since this falls within the ideal range for an oval cut (1.35 – 1.50), the diamond has desirable proportions.
Most Common FAQs
The ratio determines how proportionate and visually appealing a diamond appears. It also impacts how light reflects within the stone, affecting its brilliance.
Not necessarily. The ideal ratio depends on the diamond shape. Some cuts, like round diamonds, require a near 1:1 ratio, while elongated shapes like marquise or oval have higher ratios.
By inputting the diamond’s length and width, you can quickly determine whether it falls within the ideal proportions for its shape, helping you make an informed decision.