How to Optimize CSS Delivery to Improve WordPress Site Speed


Website speed is crucial for user experience and SEO. One of the key factors affecting your WordPress site’s speed is how CSS is delivered. In this article, we’ll explore techniques to optimize CSS delivery and significantly improve your WordPress site’s performance.

Reduce Render-Blocking CSS

Render-blocking CSS can delay the rendering of your web pages, leading to slower load times. To reduce render-blocking CSS:

  • Identify critical CSS: Determine the essential CSS required to render the above-the-fold content.
  • Inline critical CSS: Place the critical CSS directly in the HTML document’s <head> section.
  • Load remaining CSS asynchronously: Use the media="print" attribute and JavaScript to load non-critical CSS files asynchronously.

Asynchronous CSS Loading

Loading CSS files asynchronously allows the browser to render the page without waiting for the CSS files to download. You can achieve this by:

  • Adding the media="print" attribute to your <link> tags.
  • Using JavaScript to change the media attribute to “all” once the CSS files are loaded.
<link rel="stylesheet" href="styles.css" media="print" onload="'all'">

Eliminate Unused CSS

Unused CSS can bloat your stylesheet and slow down your site. Tools like PurifyCSS, UnCSS, and PurgeCSS can help you identify and remove unused CSS from your WordPress theme and plugins.

Minify CSS Files

Minification reduces the size of your CSS files by removing unnecessary characters, such as whitespace and comments. Use tools like CSSNano, Clean-CSS, or online minification services to minify your CSS files.


Optimizing CSS delivery is a crucial step in improving your WordPress site’s speed. By reducing render-blocking CSS, loading CSS asynchronously, eliminating unused CSS, and minifying your CSS files, you can enhance your site’s performance and provide a better user experience.

Implement these strategies today and watch your WordPress site load faster than ever before!

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