Remove Duplicate CSS

Stylesheets that grow over months or years — especially ones touched by more than one person — tend to accumulate duplicate selectors and redundant property declarations that nobody notices until the file is bloated and confusing to debug. Paste in a stylesheet and this tool scans for exact duplicate rules, selectors repeated with overlapping properties, and redundant declarations that get overridden later in the same file anyway, then outputs a cleaned version with the duplication stripped out and the effective styling left unchanged. It’s a common first step before a larger refactor, or just a periodic cleanup pass on a stylesheet that’s been growing without much oversight.

FAQ

Will removing duplicates change how my page actually looks? 

No — the tool only removes rules that are genuinely redundant (exact repeats, or earlier declarations fully overridden by a later one with equal or higher specificity), so the computed styles applied to your page stay identical; only the file gets smaller and easier to read.

What if two rules look like duplicates but have different specificity? 

Those are left alone — a selector repeated with different specificity isn’t a true duplicate, since removing either one could change which rule wins in the cascade. The tool only flags cases where removal provably has no effect on the final rendered output.

Does this handle CSS custom properties (variables) as well as regular rules? 

Yes — duplicate or redundant custom property declarations (--color-primary set twice with the second value simply overriding the first) are flagged the same way as regular property duplicates.

If the goal is reducing file size generally rather than just removing redundancy, running the cleaned output through the HTML / CSS minifier afterward strips whitespace and comments for an additional, smaller reduction on top of the duplicate removal.