How to optimize the PageSpeed Insights score
PageSpeed Insights (Lighthouse) score is the simplest way to measure site’s performance. However, it’s also very imprecise and doesn’t affect SEO. This means you shouldn’t invest too much effort into it.
Maybe don’t optimize it (because it doesn’t matter)
PageSpeed Insights don’t affect SEO
PageSpeed Insights don’t affect your SEO, Core Web Vitals do (proof, more proof). The difference between two is that PageSpeed Insights runs a test on a fake slow Android phone, whereas Core Web Vitals collect data from your real visitors (more about this).
As a result, often, your PageSpeed Insights score won’t be green even when the Core Web Vitals are all green. You can ignore PageSpeed Insights when that happens.
The best place to see your Core Web Vitals is the Search Console: https://search.google.com/search-console/core-web-vitals
PageSpeed Insights recommendations are bad
PageSpeed Insights recommendations are notoriously imprecise. We’ve seen multiple cases where implementing them had no effect on the real-world performance, or even on the PageSpeed Insights’ own performance score. Here’s one.
If you do, avoid common pitfalls
Run several tests
The PageSpeed Insights score varies between runs, sometimes up to 15 points. To get a more realistic value, run the test at least three times and pick the median or average.
(You’ll need to wait a few minutes after running every test, as PageSpeed Insights shows the same result if you re-run the test immediately. Or, to avoid waiting, append ? and a new random number to the end of the URL on every test, like my-site.com/my-page/?1234.)
Follow performance best practices
See the list of best practices for images, fonts, and more.