What the Scores Mean
Enter a web address and the analyser runs a lab test of how quickly the page loads and becomes usable, on either a simulated mobile or desktop device. Scores run from 0 to 100: 90 and above is good, 50 to 89 needs improvement, and below 50 is poor.
Google uses three Core Web Vitals as a ranking signal:
- Largest Contentful Paint (LCP): how long the main content takes to appear. Aim for 2.5 seconds or less.
- Interaction to Next Paint (INP): how quickly the page responds when someone taps or clicks. Aim for 200 milliseconds or less.
- Cumulative Layout Shift (CLS): how much the page jumps around while loading. Aim for 0.1 or less.
The fixes that usually matter most
- Compress and correctly size images, and give them width and height so space is reserved.
- Reserve space for ads and embeds so they don't push content down.
- Remove or defer JavaScript the page doesn't need straight away.
- Serve text through a CDN with compression switched on.
Lab scores change from run to run by a few points, so test two or three times. Real-visitor data in Google Search Console is the figure Google actually uses.
Frequently asked questions
Why is my mobile score lower than desktop?
Mobile tests simulate a mid-range phone on a slower connection, so heavy scripts and large images cost much more time. Most sites score lower on mobile.
Why does the score change each time I test?
Network conditions, server response time and third-party scripts such as ads vary between runs. Differences of a few points are normal.
What is a good Core Web Vitals score?
LCP of 2.5 seconds or less, INP of 200 milliseconds or less, and CLS of 0.1 or less, measured for at least 75% of real visits.