Calculate emerald cut length-to-width ratio, length, or width with millimeter, inch, foot, centimeter, or meter units.
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Emerald Cut Ratio Formula
The emerald cut ratio is the length-to-width ratio of the stone or rectangular shape. Choose the ratio, length, or width calculation and enter the two known values.
- R = emerald cut ratio, also called length-to-width ratio
- L = length
- W = width
If you enter length and width, the calculator divides length by width to find the ratio. If you enter width and ratio, it multiplies them to find length. If you enter length and ratio, it divides length by ratio to find width.
Length and width can be entered in different units. The calculator applies exact unit factors to compare measurements in a common unit, then expresses a missing dimension in the selected result unit.
Illustrative Emerald Cut Length-to-Width Ratios
Length-to-width ratio describes the outline. Lower ratios look squarer; higher ratios look more elongated. The ranges below are descriptive examples, not cut grades or universal quality standards. GIA notes that personal preference matters and identifies 1.50:1 to 1.75:1 as popular for emerald-cut diamonds.
| Ratio | General Appearance | Notes |
|---|---|---|
| 1.00 to 1.10 | Nearly square | Closer to an Asscher-style outline than a classic emerald rectangle. |
| 1.20 to 1.30 | Slightly rectangular | A shorter emerald cut shape. |
| 1.35 to 1.50 | Rectangular outline | An illustrative range; no ratio alone establishes cut quality. |
| 1.50 to 1.75 | Long rectangular | Looks more elongated on the finger or in a setting. |
| Above 1.75 | Very elongated | The preferred outline depends on personal preference. |
Unit Conversions Used for Length and Width
| Unit | Converted to Inches |
|---|---|
| 1 inch | 1 in |
| 1 foot | 12 in |
| 1 centimeter | ≈ 0.3937007874 in |
| 1 meter | ≈ 39.3700787402 in |
Example Emerald Cut Ratio Calculations
Example 1: Find the emerald cut ratio
Suppose the length is 9 mm and the width is 6 mm. Since both dimensions use the same unit, divide length by width.
Ratio = 9 ÷ 6 = 1.50
The emerald cut ratio is 1.50, which describes a rectangular outline.
Example 2: Find the width
Suppose the length is 10 mm and the desired emerald cut ratio is 1.40.
Width = 10 ÷ 1.40 = 7.1429 mm
The width is about 7.14 mm.
FAQ
What is a good emerald cut ratio?
There is no universally best ratio. GIA identifies 1.50:1 to 1.75:1 as popular for emerald-cut diamonds, while noting the role of personal preference. Ratio describes outline and does not establish cut quality.
Does the ratio depend on the unit I use?
No. The ratio does not depend on the unit as long as length and width represent the same real measurements. For example, 9 mm divided by 6 mm gives the same ratio as the equivalent measurements in inches. If you enter different units, the calculator converts them before calculating.
Is a higher emerald cut ratio better?
Not automatically. A higher ratio means the shape is more elongated, but better depends on the look you want and the setting. Personal preference, optical performance, durability and the setting matter beyond the outline ratio.
