CSS Minifier Developer
Strip comments and whitespace from CSS and see the saving.
CSS Minifier is a free online tool that strip comments and whitespace from CSS and see the saving. It runs entirely in your web browser using plain JavaScript, so files are processed on your own device and never uploaded to a server. There is no sign-up, no file size limit imposed by the site, no watermark and no paid tier.
- Price
- Free — no account, no quota, no watermark
- Category
- Developer
- Where it runs
- In your browser, on your device
- Files uploaded
- None
- Technology
- plain JavaScript
- Settings
- None — it just works
- Works offline
- Yes, after the first visit
About CSS Minifier
Comments go, whitespace collapses, the final semicolon in each block is dropped, and color values are shortened where an equivalent shorter form exists. What is deliberately not done is reordering or merging rules: CSS cascade order is semantic, and a minifier that merges selectors can silently change specificity and which rule wins. Safety is worth more than the extra few percent.
How to use it
- Paste the text you want to run through css minifier.
- There is nothing to configure — the result updates as you type.
Under the hood
| Runs on | plain JavaScript — runs the whole thing |
Questions
Does it break CSS hacks?
Legacy hacks that rely on malformed syntax — the star hack, the underscore hack — may not survive, since they depend on parse errors. Modern feature queries and `@supports` are untouched.
Why not merge duplicate selectors?
Because order determines which declaration wins when specificity ties. Moving a rule can change rendering, and a minifier should never do that.