📖 What is CSS Minifier?
A CSS minifier compresses your stylesheets by removing whitespace, line breaks, comments and unnecessary characters — without changing how the CSS works. The result is a smaller file that loads faster in the browser, improving page performance and Core Web Vitals scores.
Paste your CSS and get the minified output instantly. This tool runs entirely in your browser — your stylesheets are never uploaded to any server. Use it for quick one-off minification, or to check how much a build tool would save.
💡 Example
Input
.header {
background-color: #333;
/* Main header */
padding: 20px;
}
Output
.header{background-color:#333;padding:20px}
🛠️ Common Use Cases
- Reducing CSS file size before deploying to production
- Quick-checking how much your CSS compresses without setting up a build tool
- Minifying inline CSS for HTML email templates
- Preparing CSS for embedding in JavaScript bundles
- Comparing original vs minified size to find bloated stylesheets
📝 What CSS Minification Removes
- Whitespace — spaces, tabs, newlines between rules and properties
- Comments —
/* ... */ blocks (except /*! license comments in some tools)
- Semicolons — the last semicolon before a closing brace is optional
- Redundant zeros —
0.5em → .5em, 0px → 0
- Redundant units —
margin: 0px → margin:0
Advanced minifiers (like cssnano in build pipelines) also merge duplicate selectors, shorten colors (#ffffff → #fff) and optimize shorthand properties.
⚠️ Common Mistakes
- Minifying during development — always work with readable CSS and only minify for production. Use source maps if you need to debug minified CSS.
- Forgetting to test after minification — aggressive minification can occasionally break CSS that relies on specific whitespace (e.g. in
calc() expressions). Always test the result.
- Double-minifying — running already-minified CSS through a minifier again wastes time and produces no additional savings
- Not combining with gzip — minification + gzip compression together typically reduce CSS by 80-90%
❓ Frequently Asked Questions
How much smaller will my CSS get? ▾
Typical savings are 20-40% from minification alone. Combined with gzip compression on your server, total savings reach 80-90%. The exact reduction depends on how much whitespace and comments your original CSS contains.
Will minified CSS look the same in the browser? ▾
Yes — minification only removes characters that do not affect rendering. The CSS rules, selectors and property values are preserved exactly.
Should I use this instead of a build tool? ▾
For production workflows, use a build tool like cssnano, PostCSS or a bundler (Vite, Webpack). Use this tool for quick one-off minification, checking compression ratios, or when you do not have a build pipeline set up.
Is my data private? ▾
Yes — all processing runs entirely in your browser using JavaScript. Your data is never sent to any server.
Is this tool free? ▾
Completely free — no login, no usage limits, and it works offline once the page is loaded.
Yes — completely free, no login required, no usage limits.
Is my data private? ▾
Yes — all processing runs in your browser. Your data is never sent to any server.
Does it work offline? ▾
Yes — once the page is loaded, the tool works without an internet connection.