Duplicate CSS Remover

Style.Tools, a free CSS optimization widget, provides access to an advanced duplicate CSS remover.


The duplicate CSS remover provides many options for tuning the duplicate CSS remover and PostCSS parser.

The configuration is 100% JSON and is available in a JSON schema.


By default, the duplicate CSS remover simply removes duplicate code found in an other stylesheet. The configuration enables to fine tune the PostCSS parser and what selectors and properties to preserve or to forcefully remove.

"atRulesToKeep": [],
"atRulesToRemove": [],
"selectorsToKeep": [],
"selectorsToRemove": [],
"propertiesToKeep": [],
"propertiesToRemove": [],
"strictParser": false

The second input field accepts the stylesheet index number. You can find the index of a stylesheet on the stylesheet overview on the settings tab.

Stylesheet index

If you want to upload stylesheet or compare stylesheets from external URL(s), you can simply create a new stylesheet and import URLs or upload the stylesheets and use the index from the new sheet in the duplicate CSS remover. It takes just a few clicks.

Import URLs or upload multiple stylesheets

Once configured, simply press the button to start the duplicate CSS remover. A CSS comment will display basic statistics of the resulting reduced CSS.

Duplicate CSS remover result