Core Web Vitals explained for business owners

Core Web Vitals are Google’s measurements of how a web page feels to use: how quickly it loads, how quickly it responds and how stable it is while loading. They affect how customers experience your site and form part of how Google assesses page experience. Here is what they mean in plain English.

The three Core Web Vitals

Largest Contentful Paint (LCP): how quickly the page loads

LCP measures how long it takes for the largest visible element on the screen, usually a hero image or headline, to appear. A good LCP is 2.5 seconds or less. Slow LCP is usually caused by large images, slow hosting or too much code loading before the page can render.

Interaction to Next Paint (INP): how quickly the page responds

INP measures how quickly the page reacts when someone taps, clicks or types. It replaced an older measure, First Input Delay, in 2024. A good INP is 200 milliseconds or less. Poor INP is usually caused by heavy JavaScript, such as page builders, sliders, chat widgets and tracking scripts competing for the browser’s attention.

Cumulative Layout Shift (CLS): how stable the page is

CLS measures how much the page jumps around while it loads, for example when an image or banner appears and pushes the text down just as someone goes to tap a button. A good CLS is 0.1 or less. It is usually caused by images without set dimensions, late-loading adverts or cookie banners, and fonts that change size as they load.

How Google measures them

Google uses real visits from Chrome users, not just a lab test. A page passes when at least 75% of visits meet the “good” threshold for each measure. That is why a site can score well in a one-off test on a fast office connection and still struggle with real customers on phones.

You can see your own figures in Google Search Console, under the Core Web Vitals report, and test individual pages with PageSpeed Insights.

Why they matter for your business

• Customers notice. A slow or jumpy page feels untrustworthy and people leave, particularly on mobile.
• Conversions depend on it. Booking and checkout journeys are especially sensitive to delays.
• Search visibility. Page experience is one of many signals Google considers. Good content still matters most, but a fast site removes a disadvantage.

The fixes that usually make the biggest difference

1. Optimise images. Serve modern formats such as WebP or AVIF, size them correctly for each screen and lazy-load anything below the fold.
2. Remove unnecessary JavaScript. Heavy themes, page builders and unused plugins are the most common cause of poor INP on WordPress sites.
3. Use good hosting and caching. A fast server response underpins everything else.
4. Reserve space for everything. Give images, embeds and banners set dimensions so the layout does not shift.
5. Load fonts efficiently. Self-host a small number of font files and preload the one used in your headings.
6. Audit third-party scripts. Chat widgets, heatmaps and tracking tags all add weight. Keep the ones that earn their place.

Build it in rather than bolt it on

Performance plugins can help, but they are treating symptoms. The most reliable way to pass Core Web Vitals is to build the site lean in the first place, with clean code, minimal JavaScript and a design system that does not depend on heavy page builders. That is how we approach every website we build.

Planning a new site? Read our website redesign SEO checklist so you keep the search visibility you already have.

Frequently asked questions