---
title: "Cut Grading Tool: meaning in gemology"
description: "The Cut Grading Tool is a free Digital Gemology tool that grades a round brilliant diamond's cut from its proportions. It reads GIA's published cut grade…"
url: https://digitalgemology.com/learn/glossary/cut-grading-tool
image: https://digitalgemology.com/img/og-digital-gemology.png?v=d224fb01
---

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[Glossary](https://digitalgemology.com/learn/glossary) · How we measure

# Cut Grading Tool

Also called cut grade estimator

The Cut Grading Tool is a free Digital Gemology tool that grades a round brilliant diamond's cut from its proportions. It reads GIA's published cut grade estimation tables; it is for education and does not give a GIA grade.

## In more detail

The tables hold 14,652 graded cells: 18 table sizes, each a grid of 37 crown by 22 pavilion angles. Table sizes run from 50% to 67%. The grade is the worst of the grid cell, the limits on the other proportions, and the finish grades. Digital Gemology is not affiliated with GIA.

## How we measure it

We read the tables from the vector data of the published document, with no interpolation. Brilliance is traced on the T73; fire and scintillation are modeled, not traced. It shows 815 light maps: one per crown and pavilion cell at a 53% table, and the T73 as cut.

## Related terms

- [Cut grade](https://digitalgemology.com/learn/glossary/cut-grade): The cut grade rates how well a diamond's proportions and finish work, from Excellent to Poor. GIA gives it only to standard round brilliants in the D-to-Z color range.
- [Brilliance](https://digitalgemology.com/learn/glossary/brilliance): Brilliance is the white light that a cut stone returns to the viewer. In our census, it is the share of entering light that leaves through the crown toward the viewer.
- [Light map](https://digitalgemology.com/learn/glossary/light-map): A light map is a face-up picture of a cut stone, colored by the direction each point's light came from. Red is direct light, green is indirect light, blue is contrast, and a dark color is leakage.
- [Crown angle](https://digitalgemology.com/learn/glossary/crown-angle): The crown angle is the slope of the bezel facets, measured against the plane of the girdle.
- [Pavilion angle](https://digitalgemology.com/learn/glossary/pavilion-angle): The pavilion angle is the slope of the pavilion mains, measured against the plane of the girdle.
- [T73 benchmark](https://digitalgemology.com/learn/glossary/t73-benchmark): The T73 benchmark is the round brilliant that our tools compare every cut with, in the same gemstone. It has Tolkowsky's 1919 angles and table, and 73 facets: 57 plus 16 girdle facets.

## Learn more

- [Cut Grading Tool](https://digitalgemology.com/tools/cut-grading-tool)
- [Cut Grading Tool](https://digitalgemology.com/about/how-we-measure/cut-grading-tool)

[All 328 terms](https://digitalgemology.com/learn/glossary)