---
title: "Interferometric Fringes calculator — AperiOptic"
description: "Fringe spacing from wavelength and crossing angle. Free online optics calculator, with the formula and code snippets."
url: "https://aperioptic.com/calculators/interferometric-fringes"
---

# Interferometric Fringes calculator

Fringe spacing from wavelength and crossing angle.

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

Formula: `Λ = λ / (2·sin(θ/2))`

## Inputs

| Input | Parameter | Unit | Default |
| --- | --- | --- | --- |
| λ | `lam` | nm | 633 |
| Angle θ | `th` | ° | 10 |

## Result with the default inputs

- Fringe spacing: 3631.4302 nm
- Fringe spacing: 3.6314 µm

Open it with your own values: put each input in the address as a parameter, for example [`/calculators/interferometric-fringes?lam=633`](https://aperioptic.com/calculators/interferometric-fringes?lam=633). A unit other than the listed one goes in `<parameter>_unit`.

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

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

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