Cut Grade Estimator

Round brilliant · adjust the proportions, read the grade

The stone, the chart and its settings

  • 3D viewDrag or arrow keys to turn
  • Crown planStar 55% · lower half 80%
  • ProfileDepth ≈ 62.1%
  • Light mapDirect 67% · Indirect 4% · Contrast 24% · Leakage 5%
Chart view

Excellent

estimated cut grade

Breakdown
ComponentValueExcellent rangeCeiling

The grids assume star 55%, lower half 80% and girdle 3.0%; other values can shift the zone in ways the caps do not capture.

53%

Measured corner to corner, as a share of the diameter

34.5°
40.8°
More proportions
55%
80%
Medium3.0%

Thinnest to thickest; Auto reads it from the girdle thickness

An estimate from proportions for education only: not a grading standard, and not a substitute for a laboratory report.