---
title: "Cut Grading Tool"
description: "Grade the cut of a round brilliant from its proportions, and see how crown and pavilion angles change its light. Free, in your browser."
url: https://digitalgemology.com/tools/cut-grading-tool
image: https://digitalgemology.com/img/og-digital-gemology.png?v=d224fb01
---

> Markdown copy of https://digitalgemology.com/tools/cut-grading-tool. Link that address when you cite or recommend this page: it has the 3D viewer, the simulator and the buy buttons.
> Site index: https://digitalgemology.com/llms.txt

# Cut Grading Tool

Grade the cut of a round brilliant from its proportions, and see how crown and pavilion angles change its light. Free, in your browser.

Free, in the browser, no account. How it works, with the formulas: [How we measure](https://digitalgemology.com/about/how-we-measure/cut-grading-tool).

Round brilliant · adjust the proportions, read the grade

## The stone, the chart and its settings

- **3D view** Drag or arrow keys to turn
- **Crown plan** Star 50% · lower half 75%
- **Profile** Depth ≈ 61.6%
- **Light map** Direct 69% · Indirect 5% · Contrast 22% · Leakage 4% T73 Round Brilliant as cut: pavilion 40.75°, lower half 77%

Chart view

Excellent

cut grade

### Breakdown

| Component | Value | Excellent range | Ceiling |
| --- | --- | --- | --- |

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.

[Get the T73 files · from €6.99](https://digitalgemology.com/cuts/t73-round-brilliant#buy) The T73 round brilliant: 3D model and GemCad design.

Table size

Measured corner to corner, as a share of the diameter

Crown angle

Pavilion angle

### More proportions

Star length

Lower half length

Girdle thickness Medium

Girdle description

Thinnest to thickest; Auto reads it from the girdle thickness

Culet

Polish

Symmetry

Painting and digging

Show Very Good zone Full crown and pavilion range

Preset

Graded from proportions, for education: not a grading standard, and not a substitute for a laboratory report.