Your PageSpeed Score Is Not Your Speed
The number in Google PageSpeed Insights is a laboratory test: one simulated mid-range phone on a throttled connection, run once. It is a useful diagnostic and a terrible target.
What Google actually uses for ranking is field data — the loading experience of real visitors on real devices over the past month, which appears at the top of the same report when your site has enough traffic. A site can score 45 in the lab and pass on field data, or score 90 and still feel slow to someone on patchy mobile data in the evening.
So the honest question is not “what is my score” but “what do my visitors experience”. The two usually move together, which is why the score is worth fixing — but chasing the last ten points is where money stops working.
What Actually Moves the Number, In Order
- Images. Almost always the largest thing on the page and almost always uploaded at the wrong size. Our guide on image optimisation for a website covers this on its own.
- Caching. The difference between building the page for every visitor and serving one that is already built.
- Plugin and script load. Every plugin adds weight, and the ones added for a campaign three years ago are still loading on every page.
- Fonts and third-party scripts. Chat widgets, analytics, ad pixels — each one is a request to somebody else’s server before your page finishes.
Hosting sits underneath all of it and is sometimes genuinely the limit, but often is not — we check before recommending a move, and our hosting and domain support page covers that side if it turns out to be the cause.
When Not to Bother
If your site already loads in about two seconds on a phone and its field data is passing, further optimisation is a poor use of money whatever the lab score says. Spend it on what the site says instead. The exception is if you are running Google Ads, where landing page experience feeds Quality Score and a faster page can genuinely lower what you pay per click.
If you would rather try it yourself first, our guide on how to speed up a WordPress website covers the same steps in order.