Symptom

BoltAudit reports CSS files that aren't minified — file sizes 2–3× larger than they need to be for the same rules.

Impact

  • Bigger CSS payload means longer download on slow connections.
  • Render-blocking by default — every byte of CSS delays first paint.
  • CDN bandwidth costs scale with size.

Manual fix

Most modern build tools (webpack, vite, esbuild) minify CSS automatically in production builds. For WordPress themes that ship hand-written CSS, you can:

  1. Use a build tool (cleanest, hardest to retrofit).
  2. Or install a minification plugin: Autoptimize, WP Rocket, or LiteSpeed Cache.

Apply Fix

One-click in the dashboard for sites where BoltAudit can safely minify CSS without breaking existing rules (e.g., pages already using a recognised optimization plugin). The fix re-minifies and caches the result.

Caveat

CSS minifiers occasionally break edge-case selectors (calc() expressions, nested at-rules in older syntaxes). After applying, do a quick visual check on your highest-traffic templates.

Run BoltAudit on your site

Free plugin · 1 site · 3 audits per month · no credit card.

See plans →