Performance fix guide
Significant Unused CSS
A large portion of downloaded CSS is unused on this page. Unused CSS increases download size and adds to render-blocking time.
Issue ID: CWV-UNUSED-CSS-001
Severity: minor
Impact: Low
Effort: M
Use this article when
- You need deeper remediation guidance than the issue card can show.
- You want CMS-specific steps before handing the fix to a developer.
- You want a repeatable re-check path after shipping the change.
What this issue is
A large portion of downloaded CSS is unused on this page. Unused CSS increases download size and adds to render-blocking time.
Why it matters
A large portion of downloaded CSS is unused on this page. Unused CSS increases download size and adds to render-blocking time. This affects load speed, Core Web Vitals, and how many visitors stay long enough to convert.
How we detect it
- FreeSiteAudit flags this issue when the rule for CWV-UNUSED-CSS-001 fails and the page evidence points to Performance tool.
- You can usually confirm this by checking the page source or the relevant page settings inside your CMS.
Evidence examples
Check the affected page source, rendered output, or relevant CMS setting to confirm the missing or incorrect element.
How to fix it
- 1Use PurgeCSS or similar tools to remove unused styles
- 2Split CSS by route or component
- 3Use Chrome DevTools Coverage tab to identify unused rules
How to re-check it
- Confirm reduced unused CSS bytes in Coverage tab
Related tools
This issue is best verified with the full FreeSiteAudit crawl rather than a single-point mini tool.