Learn Princess Length to Width:

The length to width ratio of a princess shape diamond is important to its value. Popular diamond quality reports from GIA and other gemological laboratories do not provide length to width ratios. However, they do provide length, width, and depth measurements. Length to width ratios are determined by dividing the length measurement by the width measurement. Measurements are always calculated to the one-hundredth of a millimeter.(Example) Princess length equals 6 millimeters; princess width equals 4 millimeters; 6 millimeters divided by 4 millimeters equals a length-to-width ratio of 1.5 to 1

The best princess diamonds will have a length to width ratios between 1 to 1 and 1.5 to 1. Length to width ratios within these ranges are considered by GIA as very fine to ideal. A princess diamond's length to width ratio is largely determined by the original size of the rough diamond crystal. When a rare fine quality diamond is cut by an experienced diamond cutter, the weight and value will never be sacrificed simply to change a diamond's length to width ratio if it is within the range of 1 to 1 and 1.5 to 1. Take this time to return to our list of Certified-Plus Diamonds to choose the perfect princess cut diamond that is affordable and beautifully shaped.