You have looked after the content, worked on your keywords, added useful page after useful page, and still your rankings sit exactly where they were. The reason is usually hiding where nobody thinks to look: in the technical quality of the experience a visitor has from the second a page opens. Google has given that measurement a name, the Core Web Vitals, and it treats them as a ranking signal in their own right. The good news is that there is nothing obscure about these metrics once you grasp the logic behind them.
What the Core Web Vitals actually measure
The Core Web Vitals are three metrics that put a figure on how good a page feels, from the point of view of the person reading it. Where the old speed tests measured raw numbers, these signals try to reproduce a human perception: does the site load without a painful wait, does it answer the moment I touch it, does the content hold still in front of my eyes.
The most common causes of a poor score are set out in our article on what a slow site costs you in customers.
Google folds these measurements into what it calls page experience, a cluster of signals that bears on where you rank, particularly when two pages with comparable content are competing for the same place. A fast, fluid site will not climb the results on its own, but a slow, unstable one will hit its ceiling whatever else you do. The data comes from two sources: field readings, taken from the real browsers of your real visitors, and lab tests, simulated by tools such as PageSpeed Insights.
LCP: the speed the visitor feels
LCP, or Largest Contentful Paint, measures how long the largest visible element takes to appear, most often a banner image, a main heading or a dense block of text. It is the moment the visitor decides the page has finally arrived. The target Google has set is plain: get under the 2.5 second mark.
The usual drags are images that are too heavy, hosting with a slack response time, or scripts that block rendering. To bring the score back up, you compress images and size them properly, adopt lighter modern formats, switch on caching and stand the site on hosting that keeps up. Every resource you lighten gains ground.
INP: responsiveness to the smallest gesture
INP, Interaction to Next Paint, has replaced the old FID metric. It judges how quickly a page reacts to what the visitor does: a click on a button, a menu opening, typing into a field. If the screen stays frozen a fraction of a second too long, the impression of heaviness settles in. The threshold to aim for sits under 200 milliseconds.
The main cause of sluggishness here is an excess of JavaScript monopolizing the browser. Cutting the number of plugins, trimming third party scripts and deferring anything that is not essential to the first render makes a page far livelier. A site that is sparing with resources is, by construction, a responsive one.
CLS: the visual stability that reassures
CLS, Cumulative Layout Shift, tracks the elements that jump around during loading. You know the scene: you are about to click a link and everything shifts because an image or an advert has just come in. That instability irritates, and it costs you trust. The goal is to stay under a score of 0.1.
The remedy is to reserve the space for every image and every block from the outset, to avoid inserting content above what is already on screen, and to load fonts cleanly. A site that holds still reads as serious immediately.
How to turn everything green
The first step is to measure. PageSpeed Insights and Search Console give you a free diagnosis, metric by metric, separating field data from lab data. The pages dragging the rest down show up quickly.
When those corrections go past what you can do yourself, they fall within our technical SEO support.
These measurements belong inside a wider check: our free SEO audit in 8 checks you can run yourself places performance among the other signals worth watching.
Then comes the deeper work, which often meets the principles of sustainable web design: lighten the images, limit the scripts, look after the code and choose hosting equal to the job. Turning your Core Web Vitals green is not chasing a score for Google, it is offering a browsing experience that is pleasanter, faster and sparing with energy. The ranking is only the reward.
Frequently asked questions
What are the Core Web Vitals?
Three Google metrics that measure the perceived speed (LCP), the responsiveness (INP) and the visual stability (CLS) of a page.
Do the Core Web Vitals affect SEO?
Yes, they are part of the page experience signals Google uses to rank results.
How do you test your Core Web Vitals?
With PageSpeed Insights or Search Console, both of which draw on field and lab data.
What score should you aim for?
Green on all three: LCP under 2.5 s, INP under 200 ms and CLS under 0.1.
Also worth reading: Website design in Pau
