A slow website costs you visitors before they read a single word. Google measures this with a set of metrics called Core Web Vitals. They look at how fast a page loads, how quickly it reacts and how steady it stays while it loads.

You do not need to be a developer to understand them. Once you know what each one measures, the reports in Search Console start to make sense. You can also brief your web designer far more clearly.

What Core Web Vitals measure

Core Web Vitals are metrics that measure the real experience people have on a page. Google groups them under three areas: loading, interactivity and visual stability. Each one has a target that Google describes as good. The figures below come from the Google Search Central guide to Core Web Vitals and Google search results.

Largest Contentful Paint (LCP)

LCP measures loading performance. As the name suggests, it looks at when the largest piece of content in view appears on screen. Google’s goal is for LCP to happen within 2.5 seconds of the page starting to load. Anything slower than four seconds is rated poor.

Interaction to Next Paint (INP)

INP measures responsiveness. It reflects how quickly the page reacts when someone taps a button, opens a menu or types into a form. A good INP is 200 milliseconds or less. Anything above 500 milliseconds is rated poor.

CLS and visual stability

The third metric, known as CLS, measures visual stability. It scores how much the content jumps around while the page loads. Most people have tried to tap a link just as an image loads above it and pushes the text down. A good CLS score is 0.1 or less. Anything above 0.25 is rated poor.

How the scores are judged

The scores are not based on a single visit. Google’s web.dev team uses real page views to judge each page. A page is rated good for a metric when at least 75 per cent of page views meet the good threshold for each Core Web Vitals metric. In other words, most of your real visitors need a good experience, not just the ones on fast connections. The same thresholds apply to mobile and desktop.

Those thresholds were mostly set around what mobile sites can achieve. Mobile devices are more limited in power and often sit on weaker connections. That makes the mobile result the one to watch most closely. A site that feels fine on your office computer can still struggle on a phone.

How much they matter for rankings

Google says good Core Web Vitals line up with what its core ranking systems seek to reward. It also says there is no single page experience signal. Instead, several signals are weighed together. Relevance still comes first. Google will show the most relevant content even when the page experience is below par.

Good page experience helps most when many helpful pages compete for the same search. Google also warns that a good score does not guarantee top rankings. Chasing a perfect score purely for search may not be the best use of your time. A fast, stable site that answers the searcher’s question well is the real goal.

Speed is one part of a wider picture. Clear menus and a sensible page hierarchy matter just as much. That is why it pays to optimise your website’s structure for SEO at the same time. The two pieces of work support each other.

Other page experience checks

Core Web Vitals sit alongside a handful of other questions Google asks site owners to consider. Answering yes to these suggests a good page experience overall. They are simple enough to check yourself on a phone and a laptop.

• Are your pages served securely over HTTPS?
• Does your content display well on mobile devices?
• Do ads stay out of the way of the main content?
• Do your pages avoid intrusive pop ups that cover the content?
• Can visitors easily tell the main content apart from everything else?

None of these need special software. Open your site on your own phone and try to book, buy or make an enquiry. Note anything that slows you down or gets in the way. That simple test gives you a plain list to discuss with your developer.

Common causes of poor scores

Images are a common culprit. Google notes that images are often the largest part of a page’s weight. A huge banner photo at the top of the page can easily slow down LCP. Resizing and compressing images before upload is one of the quickest wins.

Layout jumps usually come from a few familiar sources. Google’s web.dev guidance lists images without set dimensions, ads and embeds without reserved space, content added after the page loads and web fonts. Adding width and height attributes to images is the standard fix. Reserving space for banners and embeds stops the page moving under the reader’s finger.

Animation is another trap. Moving elements by animating their top and left positions can make the page jump. The web.dev guidance recommends using the CSS transform property instead. The ideas behind minimalism and motion in web design work best when the motion is built this way.

Every extra widget, tracking tag and slider adds code the browser has to run. It is worth reviewing which ones still earn their place. Removing what you no longer use is a simple place to start. Ask your developer to test INP again after each change.

Where to check your scores

Search Console has a Core Web Vitals report that shows how your pages perform. PageSpeed Insights is another free Google tool that lets you test a single page. Start with the pages that bring in the most enquiries, such as your home page and main service pages.

Numbers only tell part of the story. Real people notice things a report will miss, such as a confusing menu or a form that is hard to fill in on a phone. Gathering website feedback from customers and staff fills in those gaps. Combine both and you will have a clear list of fixes.

Law firms, trades and health clinics all face the same pressure here. A visitor comparing several websites has little patience for one that stalls. Speed work fits neatly beside other SEO tactics for lawyers and professional services. The principle is the same for any business that relies on enquiries from search.

Frequently asked questions

Do Core Web Vitals affect my Google ranking?

They play a part, but they are not the whole story. Google says good scores align with what its ranking systems reward. Relevant, helpful content still matters more.

What is a good LCP score?

Google’s goal is an LCP of 2.5 seconds or less. Anything slower than four seconds is rated poor. The rating is based on at least 75 per cent of page views.

Why does my mobile score look worse than desktop?

Mobile devices are more limited than desktop computers. The thresholds are the same for both devices. That is why the mobile result is often where most of the work lies.

Do I need a perfect score?

No. Google says chasing a perfect score just for search may not be the best use of your time. Aim for good on each metric, then put your effort into content and usability.