Table percentage is a formula used to describe the table's proportionate surface area relative to the rest of the gem's facets, and it is an important indicator of how well a diamond will sparkle or display brilliance. The table percentage is calculated by dividing the length of the table by the total diameter. For example if the length of a diamond's table facet is 6.0mm and the total diameter of the diamond (measured at its girdle) is 10.0mm, then the table percentage of the diamond would be 60%.
See related: facets, depth, cut, depth percentage