---
title: "Bragg's Law calculator — AperiOptic"
description: "Constructive diffraction angle from a crystal lattice. Free online optics calculator, with the formula and code snippets."
url: "https://aperioptic.com/calculators/braggs-law"
---

# Bragg's Law calculator

Constructive diffraction angle from a crystal lattice.

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

Formula: `n·λ = 2·d·sin θ`

## Inputs

| Input | Parameter | Unit | Default |
| --- | --- | --- | --- |
| Wavelength λ | `lam` | nm | 0.15406 |
| Spacing d | `d` | nm | 0.314 |
| Order n | `n` |  | 1 |

## Result with the default inputs

- Bragg angle θ: 14.2007 °
- 2θ: 28.4013 °

Open it with your own values: put each input in the address as a parameter, for example [`/calculators/braggs-law?lam=0.15406`](https://aperioptic.com/calculators/braggs-law?lam=0.15406). A unit other than the listed one goes in `<parameter>_unit`.

Read more: [Wikipedia: Bragg's law](https://en.wikipedia.org/wiki/Bragg%27s_law)

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

---

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