CSS purge estimator documentation

Estimate unused CSS selectors, plan safelists, and copy purge-ready tokens with coverage context.

Overview

Use it when the format needs to change, not the meaning

Use the estimator to see which selectors survive a purge pass and which ones need safelisting.

Pre-flight checks

Review selector coverage before you ship a purge config.

Template audits

Check which classes and ids appear in your sample markup.

Safelist planning

Protect dynamic selectors before they are stripped out.

Supported inputs

Bring clean source text and keep the direction straight

  • Accepts compiled CSS and representative HTML or template snippets.
  • Safelist entries can be pasted as class names or raw selectors.
  • Dynamic classes should be included in the sample content or safelist list.

Walk through it

Follow the same sequence you see in the tool

Workflow

Scan CSS against markup

Paste both inputs to see which selectors appear used or unused.

  1. Paste the built CSS and representative content samples.
  2. Submit to generate coverage results and selector status.
  3. Review the unused list before you remove anything from the stylesheet.

What you get

Check the result before you copy it into the next step

Used selectors

Selectors that appear in the sample content are treated as kept.

Unused selectors

Potential removals are grouped so you can review them before changing the build.

Avoid these mistakes

Small input problems create the biggest conversion errors

Scanning source files instead of built CSS

Use the compiled stylesheet so the estimate matches what will ship.

Forgetting dynamic classes

Add JS-driven selectors to the safelist or include them in sample content.

Need a different utility? Browse the documentation hub for the rest of the published guides.
Last updated March 23, 2026