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How to Minify CSS / JavaScript Files in WordPress (3 Ways)

Do you want to minify files on your WordPress site?

Minifying your WordPress CSS and JavaScript files can make them load faster and speed up your WordPress site.

In this guide, we will show you how to easily minify CSS/JavaScript files in WordPress to improve performance and speed.

Easily minify CSS and JavaScript files in WordPress

What is Minification and When Do You Need it?

The term ‘minify’ is used to describe a method that makes your website file sizes smaller. It does this by removing white spaces, lines, and unnecessary characters from the source code.

Here is an example of normal CSS code:

body {
margin:20px;
padding:20px;
color:#333333;
background:#f7f7f7;
}
h1 {
font-size:32px;
color#222222;
margin-bottom:10px;
}

After minifying the code it will look like this:

body{margin:20px;padding:20px;color:#333;background:#f7f7f7}
h1{font-size:32px;margin-bottom:10px}

Usually, it is recommended to only minify files that are sent to user’s browsers. This includes HTML, CSS, and JavaScript files.

You can minify PHP files too, but minifying it will not improve page load speed for your users. That’s because PHP is a server-side programming language, meaning it runs on servers before anything is sent to the visitor’s web browser.

The advantage of minifying files is improved WordPress speed and performance, since compact files are faster to load.

However, some experts believe that the performance improvement is very small for most websites and not worth the trouble. Minification only removes a few kilobytes of data on most WordPress sites. You can reduce more page load time by optimizing images for the web.

If you are trying to achieve 100/100 score on Google Pagespeed or GTMetrix tool, then minifying CSS and JavaScript will significantly improve your score.

Having said that, let’s take a look at how to easily minify CSS/JavaScript on your WordPress site.

We’ll go over 3 different options you can choose from:

Ready? Let’s get started with our top recommended method.

Method 1. Minify CSS/JavaScript in WordPress Using WP Rocket

This method is easier and is recommended for all users. It works regardless of which WordPress hosting you are using.

First, you need to install and activate the WP Rocket plugin. For more details, see our step by step guide on how to install a WordPress plugin.

WP Rocket is the best WordPress caching plugin on the market. It allows you to easily add caching to WordPress and significantly improve website speed and page load times.

For more details, see our tutorial on how to install and set up WP Rocket in WordPress.

Upon activation, you need to visit the Settings » WP Rocket page and switch to the ‘File Optimization’ tab.

Minify CSS files in WP Rocket

From here, you need to check the Minify CSS files option.

WP Rocket will then show you a warning that this could break things on your site. Go ahead and click on the ‘Activate Minify CSS’ button. You can always deactivate this option if it causes any issues with your website.

Activate CSS minify

Next, you need to scroll down to the JavaScript Files section below.

Here, simply check the box next to the ‘Minify JavaScript files’ option.

WP Rocket minify JavaScript files

Again, you’ll see a warning that this could break things on your site. Go ahead and click on the ‘Activate Minify JavaScript’ button.

After that, don’t forget to click on the Save changes button to store your settings.

WP Rocket will now start minifying your CSS and JavaScript files. You can clear your cache in the plugin settings to make sure that it starts using the minified CSS and JavaScript for the next website visitor.

Method 2. Minify CSS/JavaScript in WordPress Using SiteGround

If you are using SiteGround as your WordPress hosting provider, then you can minify CSS files using SiteGround Optimizer.

SiteGround Optimizer is a performance optimization plugin that works on their own platform. It works well with their Ultrafast PHP to improve your site’s loading times.

Simply install and activate the SiteGround Optimizer plugin on your WordPress site. For more details, see our step by step guide on how to install a WordPress plugin.

After that, you need to click on the SG Optimizer menu in your WordPress admin sidebar.

SG Optimizer

This will take you to SG Optimizer settings.

From here you need to click on the ‘Go To Frontend’ button under ‘Other Optimizations’.

SiteGround frontend optimization

On the next screen, you need to switch on the toggle next to the ‘Minify CSS files’ option.

Minify CSS in SiteGround

Next, you need to switch to the JavaScript tab and turn on the toggle next to ‘Minify JavaScript Files’ option.

That’s all! You can now empty your WordPress cache and visit your website to load minified versions of CSS and JS files.

Method 3. Minify CSS/JavaScript using Autoptimize

This method is recommended for users who are not on SiteGround and not using WP Rocket.

First, you need to install and activate the Autoptimize plugin. For more details, see our step by step guide on how to install a WordPress plugin.

Upon activation, you need to visit the Settings » Autoptimize page to configure the plugin settings.

From here, first you need to check the option ‘Optimize JavaScript Code’ under JavaScript Options.

Autoptimize JavaScript options

After that, you need to scroll down to the CSS Options and check the box next to the ‘Optimize CSS code’ option.

Autoptimize CSS code

Don’t forget to click on Save Changes button to store your settings.

Then you can click the Empty Cache button to start using your minified files. The plugin can also be used to fix render blocking JavaScript and CSS in WordPress.

We hope this article helped you minify CSS and JavaScript on your WordPress site. You may also want to see our tutorial on optimizing core web vitals in WordPress and follow our ultimate WordPress performance guide.

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Reader Interactions

21 CommentsLeave a Reply

  1. This plugin is no more available in the WordPress plugins panel. Also, it is not updated for the last 6 years.

    • Thank you for letting us know, we will be sure to look into updating this article :)

      Admin

  2. What if I am not happy with results, can I undo with a click of a button and return to non-minify state?

    • If you used the plugin then you would need to remove the plugin to stop it from minifying and clear any caching on your site.

      Admin

  3. This plugin hasn’t been tested with the latest 3 major releases of WordPress. It may no longer be maintained or supported and may have compatibility issues when used with more recent versions of WordPress.

  4. I’m looking for an outstanding Minify plugin. Reading this post I was willing to install Better WordPress Minify. Over at the WordPress repo I noticed that this plugin wasn’t updated in three years. I also noticed that there was not much going on on the support page.

    I’m sure you can understand my hesitation to install this plugin.
    Question is…. can I do it safely with the latest WordPress and php version or do you recommend another plugin at this moment.

    HTH

    Adri

    • I’m using Autoptimize for most of my websites and it’s going very well.
      It has options for minify HTML, CSS and JS files.

  5. if you are using W3 Total Cache plugin, many of the WordPress users use this plugin to increase web PageSpeed. You might be aware that this plugin offers a feature to Minify CSS, JavaScript and HTML files. I would recommend this, because it serve the purpose and you don’t need to use additional plugin for Minification.

  6. hello there,

    Once I checked the minify option from one of my cache plugin whose name I don’t know now, but it destroyed my theme. So I am in worry dost the plugin that you have suggested will do the same or it won’t destroy my theme when I install it? I have themify ultra theme.

    thanks,

    sophie.

  7. Thank you for your article. is there another plug in you might recommend? Better WordPress Minify has not been updated in 2 years. Thank you

  8. Hello,

    I enjoyed the article, but I have a suggestion. I noticed with a lot of the WP Beginner articles that they feature a plugin based solution. I think that’s great, but at times it’s nice for advanced users to see some behind the scenes stuff.

    There are a few articles that you have that show the plugin way and then a manual (for advanced WordPress users) way. I like those articles because it’s geared toward the novice and advanced WP user or developer.

    As time permits, could you please consider updating the article to feature a how to minify for advanced users/developers?

    Thanks!

    • I agree with you JERMY. But as from the website name i.e wpbeginner.com Here the word Beginner is used, which means it is not Pros.

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