---
title: "Shot Noise SNR calculator — AperiOptic"
description: "Photon-shot-noise-limited SNR from flux, QE and integration time. Free online optics calculator, with the formula and code snippets."
url: "https://aperioptic.com/calculators/shot-noise-snr"
---

# Shot Noise SNR calculator

Photon-shot-noise-limited SNR from flux, QE and integration time.

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

Formula: `SNR = √(η · Φ · t)`

## Inputs

| Input | Parameter | Unit | Default |
| --- | --- | --- | --- |
| Photon flux Φ | `phi` | γ/s | 1000000 |
| QE η | `qe` |  | 0.7 |
| Integration t | `t` | s | 0.01 |

## Result with the default inputs

- Detected e⁻: 7000
- Shot-noise SNR: 83.666

Open it with your own values: put each input in the address as a parameter, for example [`/calculators/shot-noise-snr?phi=1000000`](https://aperioptic.com/calculators/shot-noise-snr?phi=1000000). A unit other than the listed one goes in `<parameter>_unit`.

Read more: [Wikipedia: Shot noise](https://en.wikipedia.org/wiki/Shot_noise)

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

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