Lab data
The score at the top is a simulated phone on a throttled connection, run once. It is good for finding causes but varies from run to run.
Guide · Website speed
PageSpeed Insights explained
PageSpeed Insights gives two kinds of result that people often mix up. This guide explains what each one means and what to fix first.
Two kinds of data
Lab data and real-user data.
Real-user data
The Core Web Vitals assessment uses data from Chrome users over the last 28 days. It appears only when your site has enough visitors.
They can disagree
A site can score badly in the lab and still pass for real users, and the other way round. Look at both.
The three measures
Google’s “good” thresholds.
Thresholds are from Google’s Core Web Vitals documentation at the time of writing.
LCP: Largest Contentful Paint
How long the biggest visible element takes to appear. Good is 2.5 seconds or less.
INP: Interaction to Next Paint
How quickly the page responds when someone taps or clicks. Good is 200 milliseconds or less.
CLS: Cumulative Layout Shift
How much the page jumps while loading. Good is 0.1 or less.
Why mobile is lower
The same page, a slower phone.
A slower test
PageSpeed tests mobile on a slower simulated phone and network than desktop.
The usual causes
Large images, sliders, fonts and third-party scripts hurt mobile far more than desktop.
What to fix first
In this order.
Images
Resize and compress the largest images, especially the first one on the page.
Scripts
Remove or defer scripts you do not need: chat widgets, sliders, extra tracking tags.
Layout
Reserve space for images and banners so the page stops jumping.
Test again
Test mobile first, several times, and compare with your first result.
Need help?
If the causes sit in your theme or page builder, a paid Website Health Check gives you a written list of fixes in priority order. See website speed optimisation and ways to start. Example: At Home Catering, a WordPress event-catering site, scores 98 on PageSpeed desktop (tested 23 October 2026). At Home Catering case study.
FAQ
Questions we get asked.
Short answers, in plain English.
Why does my score change every time I test?
It is a simulation, so network and server timing vary. Test several times and look at the pattern, not one number.
Does a high score improve my Google ranking?
Page experience is one of many signals, and a score is not a ranking. Fast pages are still better for visitors, who are the ones making enquiries.
Contact
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