CSS Combiner
Merge multiple CSS files into one
Input CSS Files
Combined CSS
CSS Combining Examples
Merge multiple CSS blocks into one file. Use comments to separate sections:
Reset, base, and components
The combiner concatenates all blocks. Use Sample above to load more data.
What Is a CSS Combiner?
CSS projects often split styles across multiple files—reset, base, components, utilities. A CSS combiner merges them into a single file for production. Fewer HTTP requests mean faster load times. The W3C CSS spec defines the language; build tools like Vite and Webpack do this at build time. This tool does it on demand in your browser.
Paste multiple CSS blocks or upload several .css files. The tool concatenates them into one output. It runs entirely in your browser—nothing is sent to a server. For formatting the result, use CSS Formatter. For minifying, use CSS Minifier.
How to Use This Tool
Paste or Upload CSS
Paste multiple CSS blocks into the left editor (separate with comments like /* filename.css */), or click Upload to select multiple .css files. Use Sample to load example data.
Review Combined Output
The right panel shows the merged CSS. Order is preserved. For validation, use CSS Validator. For adding vendor prefixes, use CSS Prefixer.
Copy or Download
Use Copy or Download to save the combined CSS. For converting SCSS or Less first, use SCSS to CSS or Less to CSS.
Where CSS Combining Helps
Legacy projects or hand-crafted sites may have many CSS files. Combining them reduces requests and simplifies deployment. Bootstrap and Tailwind use build pipelines; this tool offers a quick manual option. For extracting CSS from HTML, use CSS Extractor.
For formatting the combined output, use CSS Formatter. For inline styles (e.g., email), use CSS to Inline. For converting between preprocessors, use CSS to SCSS or CSS to Less.
Frequently Asked Questions
Is my data private?
Yes. Combining runs entirely in your browser. No data is sent to any server.
Does it remove duplicates?
This tool concatenates files. It does not deduplicate rules or merge selectors. For advanced optimization, use build tools like cssnano or PostCSS.
What about @import?
The tool combines the text as-is. It does not resolve @import URLs. Inline or paste the imported content manually if needed.
Can I upload multiple files?
Yes. Use the Upload button and select multiple .css files. They are combined in the order selected.
Order of files matters?
Yes. Later rules override earlier ones when specificity is equal. Arrange files in the order you want cascade to apply.