Easy Converter

CSS Minifier

Minify CSS to reduce stylesheet size by 20–40% and accelerate the rendering of your pages. The minifier removes comments and whitespace, shortens hex colours, collapses zero units and rewrites longhand properties to shorthands when safe, producing a byte-perfect, browser-compatible result.

How to use

  1. 1

    Paste CSS

    Drop your stylesheet into the input area.

  2. 2

    Pick options

    Toggle comment removal, colour shortening and longhand-to-shorthand rewriting.

  3. 3

    Download minified CSS

    Compare sizes and copy or download the minified result.

Technical details

CSS minification combines several lossless transformations: removing comments and whitespace, replacing `0px` with `0`, shortening colours (`#ffffff` → `#fff`, `rgb(255,255,255)` → `#fff`), combining margin/padding/border longhands into shorthands when all four values are present, and deduplicating identical selectors.

The minifier preserves the precise cascade order: identical rules are never reordered, so the visual result is byte-perfect with the input. Vendor prefixes (`-webkit-`, `-moz-`) are kept intact unless you explicitly enable an "autoprefix-strip" mode that drops prefixes for browsers no longer in your support matrix.

For modern CSS (custom properties, `@layer`, `:has()`), the minifier preserves them as-is — it never rewrites syntax in a way that would lose semantics. The output is valid CSS that any browser can consume directly.

On a typical Bootstrap-based project, expect a 25–35% reduction in stylesheet size, which translates into a meaningful First Contentful Paint improvement over slow networks and a small but real gain on mobile.

Frequently asked questions

Is the minification lossless?
Yes. The visual output of any HTML page is byte-perfect with the original CSS.
How much smaller will my CSS be?
Typically 20–40%, depending on how verbose the original is.
Will vendor prefixes be removed?
No, by default. An optional aggressive mode lets you drop prefixes for unsupported browser versions.
Does it minify @media queries?
Yes. Whitespace is collapsed and identical queries are merged.
Is anything sent to a server?
No. The minifier runs entirely in your browser.
Reviewed by:Easy Converter Engineering Team

This tool was tested and calibrated by our engineering team. All processing happens locally in your browser — your files and data never leave your device.