What is a diamond's table and table percentage?

The table is the large, flat facet at the top of a diamond's crown and the single biggest facet on the stone; table percentage is its diameter expressed as a ratio of the total girdle diameter. These two figures are closely linked: the table's proportions directly control how light enters and exits, which shapes the overall brightness of the diamond. For a round brilliant, IGI calculates table percentage by dividing the table diameter by the average girdle diameter, both measured in millimetres. The grading report typically identifies 53 to 58 percent as the preferred range for round stones; outside that band, light either leaks through the base or reflects unevenly, reducing brilliance. For fancy shapes, the table width at the stone's widest point is divided by the total millimetre width, appearing as the second of three measurements in the top-left corner of an IGI report. Cutters occasionally push the table beyond 58 percent to preserve carat weight, a trade-off worth knowing when comparing stones. A wider table can also make a diamond read visually larger face-up at the same carat weight. A common misconception is that a smaller table percentage alone produces more brilliance; cut grade, overall proportions, and polish quality drive light performance far more than this single figure. When reviewing an IGI certificate, check table percentage alongside depth percentage rather than treating either number in isolation.