If you run a business website, you probably use some kind of analytics. And I’m sure I won’t surprise you that Google Analytics is one of the oldest and most popular website analytics you can find.
But as you probably know, Google Analytics has it own issues. First – it’s not as private as it should be. There are various issues with it’s privacy, especially in European Union. The other thing, which started bugging me more and more, is that it slows down websites. Google Analytics speed issues may not seem significant for desktop users, but it does slow down website experience on mobile devices.
Since I’m a huge fan of privacy-focused Fathom analytics, I thought it would be a good idea to test what is the speed difference without analytics, with Google Analytics and with Fathom analytics on the same server, the same WordPress website. Here’s what I found out.
How I measured website speed when comparing Google Analytics and Fathom
If you’re looking for UltraMegaScientific analytics test, then sorry. I made the test for myself, as simple as possible, so nothing scientific here. But it’s reliable. I’ve used:
- this website’s copy in the same Hostinger VPS server
- currently latest WordPress 6.0.2 version
- slightly modified Frost theme
- no additional scripts from outside WordPress installation directory, no CDN
- WP Fastest Cache (free version) and Autoptimize for caching and minification
I’ve added both Google Analytics (latest tag manager) and Fathom scripts using the most basic way available – by adding both scripts to theme’s functions.php file using wp_head hook. Once one script is enabled, I cleared cache, opened a few website pages as a visitor to make sure caching does it’s job, and then ran a few tests using Google’s Pagespeed Insights.
I think the results are reliable. I’ve run every test at least 3 times, and the results were pretty much the same, having no more than 1% of difference in PageSpeed Insights.
WordPress website page speed without Analytics
Here’s what I got when I was testing website with both analytics scripts disabled:
- Mobile performance – 95
- Desktop performance – 98
All other stats can be seen in the screenshots (click to enlarge).
Now once we have our benchmark, let’s run the same test using Google Analytics script enabled.
WordPress website page speed with Google Analytics enabled
Now I’ve run the same pagespeed test on the same server, same website, but with Google Analytics enabled.
Here are the results:
- Mobile performance with Google Analytics enabled – 88
- Desktop performance with Google Analytics enabled – 95
Detailed results in screenshots:
As you see, after enabling Google Analytics website pagespeed on mobile dropped by 7 points, or over 7% drop.
Desktop speed drop is smaller – from 98 to 95. Basically 3% drop with Google Analytics.
WordPress website page speed with Fathom analytics script
Let’s see how WordPress page speed will change when we replace Google Analytics with Fathom analytics code. As previously, same website, same server, everything same as before.
Here are the results:
- Mobile performance with Fathom enabled – 94
- Desktop performance with Fathom enabled – 98
Detailed results from PageSpeed Insights:
Not surprising for me, but might be suprising for you – Fathom analytics script almost does not make any difference to website speed. Desktop speed is basically the same if you use Fathom or not, and mobile page speed is down only by one point – from 95 to 94. So it barely makes a difference at all!
Well, there’s not much to conclude actually. Want to have fast WordPress website, and have fast analytics without privacy issues? Then replace Google Analytics with Fathom. It may not be free in terms of financial cost, but your site visitor data will private without compromise, and you’ll have significantly faster website as well.