WP Speed Of Light Review: It Made My Test Site 48% Faster!

This article was researched and written by our experts using our in-depth Analysis Methodology.
People always tell you that you need your WordPress site to load fast. But...how do you actually make your WordPress site load fast? When you see those big lists of "75+ ways to speed up WordPress", it's easy to feel like WordPress performance is too complicated for you. WP Speed Of Light is a plugin that tries to simplify WordPress performance by giving you an all-in-one solution to speed up your site. It's simple enough for a total beginner to use, while still giving more advanced users detailed options.
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People always tell you that you need your WordPress site to load fast. But…how do you actually make your WordPress site load fast? When you see those big lists of “75+ ways to speed up WordPress”, it’s easy to feel like WordPress performance is too complicated for you.

WP Speed Of Light is a plugin that tries to simplify WordPress performance by giving you an all-in-one solution to speed up your site. It’s simple enough for a total beginner to use, while still giving more advanced users detailed options.

When I configured it on a test site, it made my test site load 48% faster. Keep reading my WP Speed Of Light review to learn more about the plugin and see if it’s right for you.

WP Speed Of Light Review: The Feature List

To help you speed up your site, WP Speed Of Light comes with an array of speed optimization features, divided into a free core version at WordPress.org as well as an optional paid add-on.

In the free version, WP Speed Of Light offers:

  • Page caching – this is the type of caching most people mean when they think of a “caching plugin“.
  • GZIP Compression – this type of compression shrinks your page’s file size, often by a significant amount.
  • Minimize requests – tries to combine multiple JS/CSS files into one.
  • Minification – shrinks file size by removing unnecessary whitespace and line breaks.
  • Remove query strings PageSpeed Insights often yells at you about this.
  • Browser cache – this lets you store static files on your visitors’ local systems to speed up load times.
  • Cache URL exclusion – you can exclude specific pages from caching so that visitors always get the latest version.
  • Speed tests – you can run overall performance tests based on WebPagetest, as well as measure database query execution time.

So all of that is for free – but here’s what you get with the Pro add-on:

  • Image compression – the Pro version includes a 1GB or 3GB quota for the ImageRecycle service.
  • Image lazy loading – lazy loading speeds up your site by waiting to load below-the-fold images until a user starts scrolling down.
  • Defer script loading – this helps with render-blocking resources.
  • Font optimization – also works with Google Fonts.
  • Cache preloading – this helps you make sure that visitors always see the static cached version of a page.
  • File exclusion for minification and grouping – this lets you exclude certain JS/CSS files via a visual interface.
  • DNS pre-fetching – this can help reduce the time it takes for DNS resolutions for external domains.
  • Database cleanup – this lets you automatically clear out junk from your WordPress site’s database.
  • User role exclusions – this lets you exclude certain user roles from seeing cached pages.

So yeah…there’s a lot going on here. But how much do all those features actually speed up your site? Let’s find out!

For reference, I’m using both the free core version and the paid add-on for this review.

Putting WP Speed Of Light To The Test

To test WP Speed Of Light, I set up a test site built with a random popular WordPress.org theme and a full Elementor template. I also have WooCommerce activated to make things a little more fun.

This site is hosted on the cheapest of cheap shared hosting, so the host certainly won’t be doing it any favors when it comes to page load times.

Here’s what I’ll do:

  • First, I’ll test the site without WP Speed Of Light (or any other performance modifications).
  • Then, I’ll run a test with the free version of WP Speed Of Light and its default beginner-friendly configuration.
  • Finally, I’ll run a third test after I’ve installed the Pro add-on and tweaked WP Speed Of Light’s settings.

Test 1: No WP Speed Of Light

Here’s the control run – without WP Speed Of Light, my test site loaded in 2.88 seconds according to Pingdom:

without plugin

Test 2: WP Speed Of Light Free Version + Default Configuration

With just the free version installed and the default configuration, my site’s page load times dropped to 1.93 seconds. You can also see that the page size went down a bit and the performance grade went up.

That’s a 33% speed increase.

with defaults

Test 3: WP Speed Of Light Pro Add-on + Custom Configuration

Finally, after I installed the Pro add-on and went through and turned on some new optimization features, my test site’s load time further dropped to 1.50 seconds. Additionally, the page size went down even further to 559.3 kB and I managed to cut off a request.

That’s a ~48% improvement vs the unoptimized page and a ~22% improvement vs the free version of WP Speed Of Light.

wp speed of light review performance

All in all, WP Speed Of Light definitely brought a major improvement to my test site’s performance.

Here’s How The WP Speed Of Light Interface Works

Now that you’ve seen the end results, let me actually go through and show you how the WP Speed Of Light interface works.

When you first install WP Speed Of Light, it gives you this neat configuration wizard to help you get set up:

wp speed of light configuration wizard

You can either:

  • Have the plugin automatically configure itself
  • Do things yourself if you prefer

beginner-friendly wizard

Performance optimization can be tricky for casual users, so it’s nice that you can just click a button and go if you want.

If you click that Beginner in optimization option, you’re pretty much done! WP Speed Of Light will then take you to this nice dashboard area where you can see a basic summary of what’s going on with your site:


This is the point at which I ran the second performance test.

Manually Configuring WP Speed Of Light

If you want to manually configure all of WP Speed Of Light’s settings, you can go to WP Speed of Light → Speed optimization in your WordPress dashboard.

Here, you can access all of the settings, divided into different tabs on the left:

caching tab

Speedup Tab

In the Speedup tab, you can control caching and lazy loading. More importantly, you can also choose to exclude specific URLs from caching or lazy loading:

WordPress Tab

In the WordPress tab, you can remove/disable some core WordPress settings, like query strings and the REST API (don’t do this if you’re using plugins that rely on the REST API):

disable wordpress features

Group & Minify Tab

In the Group & Minify tab, you can control minification and grouping for:

  • HTML
  • JS
  • CSS
  • Fonts


At the bottom, you can also use the Advanced File Exclusion feature to manually exclude certain files from minification/concatenation. This is helpful because sometimes minification/concatenation will break certain functionality – this lets you avoid that by creating manual exclusion rules using a simple visual interface:

exclude from minify

Advanced Tab

The Advanced tab lets you set up cache preloading and DNS pre-fetching:


Normally, your site only creates a cached version of a page after a user visits that specific page, which means that the first visitor doesn’t see the static cached version.

Cache preloading lets you fix that by automatically loading pages into the cache without requiring a visit.

Image Compression Tab

To access image compression, you’ll need to install the separate ImageRecycle plugin. If you’re a paid WP Speed Of Light customer, you’ll be able to optimize images for free (either 1GB or 3GB depending on your plan).

Database Cleanup Tab

The Database Cleanup tab lets you clear out junk from your database. You can also use the Automatic cleanup option to have it run every X days on autopilot, which is nice:

database cleanup

CDN Integration Tab

If you’re using a CDN, the CDN Integration tab helps you rewrite the URLs on your site to use the content hosted on your CDN. You can also exclude certain content from having its URLs rewritten:

cdn integration

Configuration Tab

Finally, the Configuration tab holds a few other helpful features.

You can:

  • Enter your WebPagetest API key to run performance tests right from the WP Speed Of Light dashboard (more on this in a second)
  • Disable optimization for certain user roles
  • Import/export your configuration settings to save time while using WP Speed Of Light on multiple sites
  • Translate WP Speed Of Light into your own language

general settings

Running Performance Tests With WP Speed Of Light

Beyond the settings above, WP Speed Of Light also helps you run two types of performance tests right from your WordPress dashboard.

First, if you get your free WebPagetest API key, you can run load time/performance tests directly from the Speed Analysis tab:

performance test

Second, you can also analyze the database queries for a specific page, which is helpful for more advanced users. Personally, I’d rather just use the Query Monitor plugin for that, though.

WP Speed Of Light Pricing: How Much Does It Cost?

Again, the core version is free and listed at WordPress.org.

If you want access to the premium features, there are two ways to get ahold of the Pro add-on, starting at just $34 for use on unlimited sites:

wp speed of light pricing

I’ve highlighted the three differences between the two pricing tiers.

Final Thoughts On WP Speed Of Light

There are two big things I like about WP Speed Of Light.

First, the data speaks for itself about the performance improvement on my test site – 48% is pretty solid!

There are a lot of quality performance plugins, though. And where I think WP Speed Of Light really excels is the interface. More specifically, making things easy for casual users.

If you’ve ever tried to configure the monstrosity that is W3 Total Cache, WP Speed Of Light is a breath of fresh air in comparison.

So if you’re looking for a way to speed up your WordPress site, give the free version a try and see how it works for you. If you like what you see, consider going Pro for even better performance.

Colin Newcomer

Colin has been using WordPress for over a decade and is on a quest to test all 60,000+ plugins at WordPress.org. He has been a Writer and Product Review Expert for WP Mayor since 2017, testing well over 150 products and services throughout that time.

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2 Responses

  1. Hi Colin

    Thanks for sharing your experience of WP Speed Of Light ! I’m using myself WP Fastest Cache Premium on a few websites (it can be really, really fast if set up correctly), and I’m really happy with the results so far.

  2. Great case study Colin, impressive results!

    I definitely want to give it a try, to see if it can shave anything off my 8+ seconds loading time.

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