Core Web Vitals are three measurements Google uses to judge how a web page feels to real visitors: how quickly the main content loads, how quickly the page responds when someone taps or clicks, and whether the layout jumps around while it loads. They are part of how Google assesses page experience, and they have a direct effect on whether visitors stay, enquire or leave.
For a UK small business, good Core Web Vitals mean a site that loads quickly on a phone over 4G, responds instantly to taps and does not make people lose their place. You can check yours for free in a few minutes, and most problems come from a handful of common causes, such as oversized images, too many plugins or slow hosting.
The three Core Web Vitals
1. Largest Contentful Paint (LCP): loading speed LCP measures how long it takes for the biggest visible element on the page, usually a hero image or headline, to appear. Google's target is 2.5 seconds or less.
2. Interaction to Next Paint (INP): responsiveness INP measures how quickly the page reacts when someone interacts with it, such as tapping a menu, pressing a button or opening a form. Google's target is 200 milliseconds or less. INP replaced the older First Input Delay measure in 2024.
3. Cumulative Layout Shift (CLS): visual stability CLS measures how much the page moves around while loading. If you have ever tried to tap a button and hit an advert that suddenly appeared, that is layout shift. Google's target is a score of 0.1 or less.
Google looks at how real visitors experience your pages, based on data from Chrome users, and a page passes when most visits meet all three targets.
Why Core Web Vitals matter for your business
- Visitors leave slow sites. Most of your customers are likely to be on mobile, often on a train, in a shop or on patchy signal. If the page takes too long, they go back to Google and pick a competitor.
- They are part of Google's page experience signals. Core Web Vitals will not make up for poor content, but when pages are otherwise similar, a better experience helps.
- Your ads cost more on slow pages. Landing page experience is part of how Google Ads judges ad quality, so a slow page can push up what you pay.
- Faster sites tend to convert better. A quick, stable page makes it easier for people to call, book or buy.
How to check your Core Web Vitals
- PageSpeed Insights (pagespeed.web.dev): enter any page address to see real-visitor data, where available, plus a lab test with specific suggestions. Always check the mobile results.
- Google Search Console: the Core Web Vitals report groups your pages into Good, Needs improvement and Poor, using real visitor data.
- Test your most important pages, not just the homepage: service pages, landing pages for ads and your contact or booking page.
If your site is new or gets few visitors, there may not be enough real-visitor data yet. Use the lab results as a guide in the meantime.
Common causes of poor scores, and how to fix them
Slow LCP
- Oversized images: resize images to the size they are displayed at and use modern formats such as WebP or AVIF.
- Slow hosting: cheap shared hosting can be slow to respond. A better host or a content delivery network (CDN) often helps.
- Heavy hero sections: large sliders and autoplaying background videos can delay the main content. Keep the top of the page simple.
- Render-blocking code: too many fonts, scripts and stylesheets loading before the page can display.
Poor INP
- Too much JavaScript: page builders, chat widgets, pop-ups and tracking scripts all add work for the browser. Remove what you do not use.
- Plugin overload: on WordPress, each plugin can add scripts. Audit them regularly.
- Third-party widgets: review embeds such as social feeds, booking widgets and live chat, and load them only where needed.
High CLS
- Images without set dimensions: give images and videos a width and height so space is reserved before they load.
- Late-loading banners and cookie notices: reserve space for them or show them in a way that does not push content down.
- Web fonts swapping in: choose font settings that minimise the jump when custom fonts load.
Quick wins you can do this week
- Compress and resize the images on your homepage and top service pages.
- Remove plugins, widgets and tracking scripts you no longer use.
- Replace an autoplaying hero video or slider with a single, well-optimised image.
- Check your hosting plan, and ask your host whether they offer caching and a CDN.
- Re-test in PageSpeed Insights and note the improvement.
For larger issues, such as a heavy theme or a site built with a slow page builder, a rebuild designed for speed is often more cost-effective than endless patching.
Frequently asked questions
Do Core Web Vitals affect my Google ranking? They are one of many signals Google uses to assess page experience. Helpful, relevant content matters most, but when competing pages are similar, a faster and more stable page can have the edge, and it will almost always convert better.
My score is different every time I test. Why? Lab tests vary with network conditions and server load. Focus on the real-visitor data in PageSpeed Insights and Search Console, which is based on actual visits over the previous 28 days.
Is a 100 score in PageSpeed Insights necessary? No. The aim is to pass all three Core Web Vitals for real visitors. Chasing a perfect lab score often brings little extra benefit.
Want a faster website?
Sundre Communications builds and optimises fast, mobile-first websites for UK businesses, designed to pass Core Web Vitals and turn visitors into enquiries. See our website development services or book a free consultation.