---
title: "Isotope Mass ↔ Energy calculator — AperiOptic"
description: "Convert atomic mass (u) to energy via E = mc². Free online optics calculator, with the formula and code snippets."
url: "https://aperioptic.com/calculators/isotope-mass-energy"
---

# Isotope Mass ↔ Energy calculator

Convert atomic mass (u) to energy via E = mc².

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

Formula: `E = m · c²`

## Inputs

| Input | Parameter | Unit | Default |
| --- | --- | --- | --- |
| Mass | `m` | u | 1 |

## Result with the default inputs

- Energy: 1.4924e-10 J
- Energy: 931.4941 MeV
- Mass: 1.6605e-27 kg

Open it with your own values: put each input in the address as a parameter, for example [`/calculators/isotope-mass-energy?m=1`](https://aperioptic.com/calculators/isotope-mass-energy?m=1). A unit other than the listed one goes in `<parameter>_unit`.

Read more: [Wikipedia: Mass–energy equivalence](https://en.wikipedia.org/wiki/Mass%E2%80%93energy_equivalence)

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

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