---
title: "Diffraction Grating calculator — AperiOptic"
description: "Diffraction angle for a grating order. Free online optics calculator, with the formula and code snippets."
url: "https://aperioptic.com/calculators/diffraction-grating"
---

# Diffraction Grating calculator

Diffraction angle for a grating order.

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

Formula: `d·sin θ = m·λ`

## Inputs

| Input | Parameter | Unit | Default |
| --- | --- | --- | --- |
| Lines/mm | `lpm` |  | 600 |
| λ | `lam` | nm | 532 |
| Order m | `m` |  | 1 |

## Result with the default inputs

- Spacing d: 1666.6667 nm
- Diff. angle: 18.6146 °

Open it with your own values: put each input in the address as a parameter, for example [`/calculators/diffraction-grating?lpm=600`](https://aperioptic.com/calculators/diffraction-grating?lpm=600). A unit other than the listed one goes in `<parameter>_unit`.

Read more: [Wikipedia: Diffraction grating](https://en.wikipedia.org/wiki/Diffraction_grating)

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

---

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