The length and width ratio of the diamond indicates its proportionate length and width. The length and width ratio signify how the diamond would look from the face i.e. top view. The L/W ratio gives an idea how big or small the stone will appear, also defining its shape. Diamonds with different ratios shape-up different; this ratio can make a princess cut diamond look rectangular, a heart skinny or bloated.
It is important to evaluate all the shapes except round since it measures the same through out. Fancy shape diamonds like Princess, Asscher, Marquise, Emerald, Radiant, Cushion, Oval, Pear, Heart etc., all have a certain basic length-to-width ratio that is considered to make the diamonds look more brilliant.
Did you know, in earlier centuries the diamond did not have any table? Strange but imagine a diamond with a pointed surface as it looked until the middle of 14th century. In fact till the 11th century diamond was used in its uncut form in jewelry. However with the introduction of the polishing wheel the face of the diamond literally began to change. As diamond cutters began to experiment, table cut became the first major faceted diamond cut. The previously pointed tip was cut to get a flat table like facet though much importance was still not given to fire and brilliance. The changing times lead to the evolution of different cuts as brilliance too started getting its due importance. Today table is an important-inseparable aspect of a diamond as people are more aware about its importance. Diamond lovers want both brilliance and fire so the demand for ideal cut diamond has gone up.
A simple formula can help get the L/W ratio of the diamond. To calculate the L/W ratio just divide the length of the diamond by its width. For e.g. a pear shaped diamond with a length of 7.5 mm and a width of 5.0 mm will have 1.50: 1 length-to-width ratio.
Length to Width Ratio = Length of the Diamond
Width of the Diamond
The diamond shape is though a matter of personal taste, but there are certain set standards to describe the best L/W ratio. Have a look at different L/W ratio variations for different shapes.