CSS Diff Checker — Compare Stylesheets Online
Paste two CSS files and instantly see every added rule, removed property, and changed value. Syntax highlighting included. No account. No limits.
Paste text in both panels above to compare
Or to see how it works
Compare CSS stylesheet versions
Paste two versions of a .css file to see exactly what changed. Great for reviewing design system updates, auditing third-party stylesheet changes, or tracing a visual regression back to the specific property that changed.
Review CSS code changes
Copy the old and new versions of a stylesheet directly from your editor or GitHub. The diff highlights added rules, removed declarations, and changed property values with character-level precision — faster than scanning a full stylesheet manually.
CSS syntax highlighting
Unlike plain text diff tools, DiffCheck applies CSS syntax coloring on top of the diff highlighting. Selectors, properties, values, and at-rules are color-coded — making it much easier to parse complex stylesheet diffs at a glance.
Spot property changes character by character
When a color hex changes from #fff to #fafafa or a spacing value shifts by 2px, character-level highlighting shows the exact difference — not just that the line changed. Find a single value change in dense CSS instantly.
Privacy-first — runs in your browser
CSS stylesheets often contain proprietary design tokens, brand colors, and unreleased UI work. DiffCheck never sends your code to any server. All comparison runs locally in JavaScript — safe for internal design systems and unreleased product work.
Works for SCSS and Sass too
Select CSS as the language and paste your .scss or .sass files. Variables, nesting, and mixins all diff cleanly — making Sass refactors easy to review without formatting issues.
How to compare CSS files online
- 1
Paste your original CSS
Put the first version of your stylesheet in the left editor — this is your baseline. Works with plain CSS, SCSS, Sass, or any CSS-like syntax.
- 2
Paste your modified CSS
Put the updated stylesheet in the right editor. This could be a refactored version, an updated dependency, or a design system change you want to review.
- 3
Read the diff
Green lines were added; red lines were removed. Within changed lines, the exact characters that differ are highlighted more intensely. CSS is selected by default for syntax coloring.
- 4
Switch views as needed
Use side-by-side to review both stylesheets in parallel columns, or switch to inline view for a compact change summary. The statistics bar shows total lines added, removed, and unchanged.
Frequently asked questions
What is a CSS diff checker?
A CSS diff checker compares two stylesheets or CSS snippets and highlights the differences — added rules, removed properties, changed values, and modified selectors. Useful for reviewing design system changes, debugging style regressions, and auditing third-party CSS updates.
Is this CSS diff tool free?
Yes, completely free with no rate limits and no signup. All CSS comparison runs in your browser — your stylesheets never leave your device.
Can I compare minified CSS?
Yes, but minified CSS is hard to diff meaningfully since all properties collapse into one line. For a useful comparison, run both stylesheets through a CSS formatter first — one declaration per line makes it easy to see exactly which properties changed.
Is my CSS safe to paste here?
Yes. All diff computation runs locally in your browser. Your stylesheets are never sent to any server, never stored, and never logged. Safe for internal design systems, unreleased UI components, or any private CSS.
Can I compare Sass or SCSS files?
Yes. Select CSS as the language for syntax highlighting. While SCSS-specific features like variables and mixins won't get dedicated highlighting, the diff will still work correctly and highlight all differences between your SCSS files.
How do I spot a specific property change?
Use character-level highlighting — within a changed line, the exact characters that differ are highlighted more intensely. This lets you spot a single value change (like a color hex or px value) inside a property declaration without reading the whole line.