Why Google measures how your site feels
Google wants to send people to pages that are useful and pleasant to use. Core Web Vitals are its way of measuring the “pleasant to use” part, based on data from real Chrome users visiting your site rather than a lab test.
They are one of many ranking signals, so a fast site will not outrank a more relevant one on speed alone. But when competing pages are similar, experience can tip the balance, and a slow site loses enquiries whatever its ranking.
The three measurements in plain English
- Largest Contentful Paint (LCP) measures how long the biggest visible element, usually a hero image or headline, takes to appear. Aim for 2.5 seconds or less.
- Interaction to Next Paint (INP) measures how quickly the page reacts when someone taps a button, opens a menu or types into a form. Aim for 200 milliseconds or less. INP replaced the older First Input Delay measure in 2024.
- Cumulative Layout Shift (CLS) measures how much the page jumps around while it loads, the familiar moment when a button moves just as you go to tap it. Aim for a score of 0.1 or less.
How the scores are judged
Google looks at the experience of the 75th percentile of your visitors, on mobile and desktop separately. In practice that means most of your visitors, including those on older phones and patchy signal, need a good experience for the page to pass.
You can see your own results in Google Search Console under the Core Web Vitals report, or by entering a page into PageSpeed Insights. If your site does not yet have enough traffic for field data, the lab scores give a useful indication.
What usually slows a business website down
- Oversized images that have not been resized or converted to modern formats such as WebP.
- Page builders and plugins loading scripts and styles on every page, whether they are needed or not.
- Cheap, overcrowded hosting that is slow to respond before the page even starts to load.
- Chat widgets, sliders, tracking tags and embedded videos that compete for the browser’s attention.
- Fonts, adverts and banners that load late and push content around.
Speed is a design decision, not a bolt-on
The fastest sites are fast because they were planned that way: lean themes, carefully chosen plugins, properly sized media and good hosting. Speed plugins can help, but they cannot fully fix a site that was built heavy.
That is why we treat performance as part of the brief on every WordPress website we build, host them on managed UK hosting with caching configured properly, and check speed as part of ongoing maintenance.
Next steps
If your Search Console report is showing pages that need improvement, or your site simply feels sluggish on a phone, get in touch. We can review the results with you and explain what is worth fixing first as part of our SEO service.