---
title: "Clear Aperture Checker calculator — AperiOptic"
description: "Verify a Gaussian beam fits within an optic's clear aperture. Free online optics calculator, with the formula and code snippets."
url: "https://aperioptic.com/calculators/clear-aperture-checker"
---

# Clear Aperture Checker calculator

Verify a Gaussian beam fits within an optic's clear aperture.

Category: [Optomechanics](https://aperioptic.com/calculators)

Formula: `Clip ≈ exp(−2·(CA/2)²/w²)`

## Inputs

| Input | Parameter | Unit | Default |
| --- | --- | --- | --- |
| Beam radius w | `w` | mm | 2 |
| Clear aperture Ø | `CA` | mm | 22.86 |

## Result with the default inputs

- 3σ diameter: 6 mm
- Power outside CA: 4.2739e-27 %
- OK? (CA ≥ 3σ Ø): Yes ✓

Open it with your own values: put each input in the address as a parameter, for example [`/calculators/clear-aperture-checker?w=2`](https://aperioptic.com/calculators/clear-aperture-checker?w=2). A unit other than the listed one goes in `<parameter>_unit`.

Read more: [Wikipedia: Aperture](https://en.wikipedia.org/wiki/Aperture)

[All optics calculators](https://aperioptic.com/calculators)

---

The interactive page: https://aperioptic.com/calculators/clear-aperture-checker (AperiOptic runs in the browser; free, no account). Every page of the site as Markdown: https://aperioptic.com/llms.txt