Calculate emerald cut ratio, length, or width from two known values with inch, foot, cm, or meter units for gemstone proportion calculations.

Emerald Cut Ratio Calculator

Enter any 2 values to calculate the missing variable


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Emerald Cut Ratio Formula

The emerald cut ratio is the length-to-width ratio of the stone or rectangular shape. The calculator uses the same relationship in three ways, depending on which value you leave blank.

R = L / W
L = R * W
W = L / R
  • 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 converts both measurements to inches before applying the formula, then converts the missing length or width back to the selected unit.

Common Emerald Cut Length-to-Width Ratios

Emerald cut diamonds and gemstones are usually described by their length-to-width ratio. Lower ratios look squarer, while higher ratios look longer and more rectangular.

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 Classic emerald cut A common range for balanced emerald cut proportions.
1.50 to 1.75 Long rectangular Looks more elongated on the finger or in a setting.
Above 1.75 Very elongated Less common and more dependent on personal preference.

Unit Conversions Used for Length and Width

Unit Converted to Inches
1 inch 1 in
1 foot 12 in
1 centimeter 0.393701 in
1 meter 39.3701 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 is a classic rectangular emerald cut proportion.

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?

A common emerald cut ratio is about 1.35 to 1.50. This range gives the stone a balanced rectangular shape. A lower ratio looks shorter and squarer, while a higher ratio looks longer and more slender.

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. Many people prefer a classic ratio around 1.40, while others prefer a shorter or longer outline.