Minify JS

Quickly strip comments and whitespace from JavaScript to estimate and reduce its size. Paste your code and the minified version appears instantly with a live size-saved percentage. This is a lightweight minifier for snippets and quick checks, for production builds, use a full compiler like Terser or esbuild.

JavaScript Input (151 chars)

Minified JS (112 chars · 26% smaller)

function calculateSum(a,b){const result=a+b;return result;}const x=10;const y=20;console.log(calculateSum(x,y));

This is a basic minifier. For production, use a full minifier like Terser or esbuild.

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Why use Minify JS?

Minifying JavaScript reduces file size by removing the characters that exist for humans, comments, indentation, and blank lines, so the browser downloads and parses less. For a one-off snippet or an inline script on a static page, that quick reduction is all you need. Under the hood it is a chain of text replacements: strip line comments and block comments, collapse blank lines and runs of whitespace, and remove the space around common operators and punctuation. It is important to be honest about the limits of a lightweight, regex-based minifier: it does not build a full syntax tree, so it cannot safely rename variables, remove unreachable code, or guarantee correctness around tricky constructs like regular-expression literals and automatic semicolon insertion. That is why every serious build pipeline uses a parser-based tool such as Terser or esbuild. Use this tool for quick estimates and simple code, test the output, and reach for a real compiler when you ship an application.

Key benefits

Instant size estimate with a live savings percentage
Removes line comments, block comments, and extra whitespace
Runs in your browser, your source code is never uploaded
Good for trimming small snippets, inline scripts, and demos

Features

Strips single-line and block comments
Collapses whitespace and blank lines
Live character count and size-saved percentage
One-click copy

Popular use cases

Estimating how much a script will shrink before adding a real build tool
Compacting a tiny inline script for a static HTML page
Cleaning comments out of a code sample before sharing

How to use Minify JS

1
Paste your JavaScript
Put your code into the "JavaScript Input" box; the character count updates live.
2
Review the minified output
The compressed code and its size saving appear instantly on the right.
3
Check the size saved
The label above the output shows the new character count and the percentage saved, useful for a quick before-and-after comparison.
4
Copy the result
Click "Copy Minified" to use the smaller version, after testing it for your use case.

Frequently asked questions

Can I use this minified output in production?

For small, simple snippets, often yes, but test it first. This is a regex-based minifier, so for application bundles you should use Terser or esbuild, which understand JavaScript syntax and minify safely.

Could minifying break my code?

It can, in edge cases. Regex-based minification does not fully parse the language, so code that relies on regex literals, template strings, or automatic semicolon insertion can occasionally be affected. Always run your tests after minifying.

Does it rename variables or mangle names?

No. It only removes comments and whitespace. It does not shorten variable names or perform dead-code elimination, things a full compiler like Terser does.

Is my code private?

Yes. Minification happens entirely in your browser; your source is never sent anywhere.

Will it mishandle two slashes inside a string or URL?

It can. The comment stripper looks for a double-slash anywhere on a line, including inside quoted strings, so a value like a full URL can have everything after those slashes removed. Check the output carefully if your code contains URLs, and use a real parser-based minifier for anything that matters.

Last reviewed: July 2026

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