Core Web Vitals are three measurements Google uses to describe how a page feels to a real visitor: how fast the main content appears, how quickly the page responds when you tap or click, and whether things jump around while it loads. You do not need to be a developer to understand them, and you do not need a perfect score to benefit from improving them.
The three metrics in plain language
| Metric | What it measures | Good target |
|---|---|---|
| LCP Largest Contentful Paint | How long the biggest visible element, usually a photo or headline, takes to appear | Under 2.5 seconds |
| INP Interaction to Next Paint | How quickly the page reacts after someone taps, clicks or types | Under 200 milliseconds |
| CLS Cumulative Layout Shift | How much the layout moves unexpectedly while loading | Under 0.1 |
These targets are measured for most real visitors rather than a single test. INP replaced an older measure called First Input Delay in March 2024.
Why it matters to your business
Slow, jumpy pages lose people. Someone on a phone who waits too long or taps the wrong button because the layout moved will often leave. Google has said page experience is one of many signals it uses, and that relevant, helpful content can still rank when a page is not perfect. So treat Core Web Vitals as a way to make the site better for visitors first, with a possible search benefit second.
What usually causes poor scores
- Oversized images. A 4,000-pixel photo shown in a 600-pixel space is the most common cause of slow LCP.
- Too many scripts. Chat widgets, trackers, sliders and pop-ups all compete for the browser's attention and hurt INP.
- Slow hosting. If the server takes a long time to respond, everything after it is late.
- Images and embeds without set sizes. The browser does not know how much room to leave, so the page jumps when they load. This drives CLS.
- Late-loading fonts and banners. Text that changes size or a cookie bar that pushes content down causes layout shift.
Fixes that help the most
- Resize and compress images. Export at the size shown on screen and use modern formats such as WebP.
- Do not lazy-load the main image. Lazy loading is great for images further down the page, but the top image should load straight away.
- Set width and height on images and videos. It reserves space and stops the layout jumping.
- Remove scripts you do not need. Every third-party tool has a cost. Keep the ones that earn their place.
- Load fonts sensibly. Use a small number of font files and make sure text stays visible while they load.
- Use decent hosting and caching. A fast server and a cached page remove a lot of waiting.
How to check your own site
Google PageSpeed Insights is free. Paste in your address and it shows results for phone and desktop. If your site has enough visitors you will see real-world data, otherwise you will see a lab test, which is still useful for spotting problems. Search Console also has a Core Web Vitals report that groups your pages by status.
Keep it realisticChasing a perfect 100 can waste money. Aim for the green “good” range on your most important pages, especially the homepage and the pages that bring enquiries.
Where to start
Test your homepage and your top service page, then fix images first. It is usually the fastest improvement for the least effort. Every site we build is made mobile-first with compressed images and clean code, and our SEO plans include technical fixes like these. If you would like us to look at your site, request a free review. You can also work through the basics in our website SEO checklist.