You may have heard that Google cares about website speed, or seen “Core Web Vitals” mentioned in an SEO report. But what are they, and do they really matter for a small business website? This guide explains everything in plain English.
What are Core Web Vitals?
Core Web Vitals are three measurements Google uses to judge the real-world experience of using a web page. Rather than testing your site in a laboratory, Google collects data from real people visiting your website in the Chrome browser, then looks at how fast, responsive and stable the experience was.
The three Core Web Vitals are:
- Largest Contentful Paint (LCP): how quickly the main content of the page appears
- Interaction to Next Paint (INP): how quickly the page responds when someone taps, clicks or types
- Cumulative Layout Shift (CLS): how much the page jumps around while it loads
The targets
Google classes each measurement as good, needs improvement or poor. To pass, a page should meet these targets for at least 75% of visits:
| Measurement | Good | Poor |
|---|---|---|
| Largest Contentful Paint | 2.5 seconds or less | Over 4 seconds |
| Interaction to Next Paint | 200 milliseconds or less | Over 500 milliseconds |
| Cumulative Layout Shift | 0.1 or less | Over 0.25 |
Why do they matter?
For your visitors
People are impatient online, especially on phones. If a page takes a long time to show anything, many visitors leave before it loads. If buttons don’t respond quickly, or the page jumps just as someone goes to tap a link, it feels frustrating and untrustworthy. All of this costs you enquiries.
For your rankings
Core Web Vitals are part of the “page experience” signals Google uses in its rankings. They won’t make a poor, irrelevant page rank well, but when competing pages are similarly relevant, a better experience can help. More importantly, a slow site can quietly hold you back.
How to check your scores
The easiest way is Google’s free PageSpeed Insights tool. Enter your web address and you’ll see:
- Field data from real Chrome users (if your site gets enough visitors), which is what Google uses
- Lab data from a simulated test, which is useful for diagnosing problems
If you have Google Search Console set up, the Core Web Vitals report shows which pages across your site pass or fail.
What usually causes poor scores?
Slow LCP
- Very large images uploaded straight from a camera or phone
- Slow hosting with long server response times
- Heavy themes and page builders that load lots of code before showing content
- Hero sliders and videos at the top of the page
Poor INP
- Too much JavaScript, often from plugins, page builders and third-party widgets
- Chat widgets, social media feeds and tracking scripts competing for the browser’s attention
High CLS
- Images and adverts without set dimensions, pushing content down as they load
- Web fonts that cause text to reflow
- Cookie banners or pop-ups that push the page around
How to improve them
The fixes depend on the cause, but the most effective ones are usually:
- Optimise images: resize them to the size they’re displayed, compress them and use modern formats such as WebP or AVIF.
- Remove what you don’t need: unused plugins, widgets and scripts.
- Improve hosting: faster servers and caching can make a dramatic difference to LCP.
- Load scripts carefully: defer non-essential JavaScript until after the page has loaded.
- Reserve space: set image dimensions and load fonts in a way that avoids layout shifts.
For sites built on very heavy page builders, the most effective long-term fix is often a rebuild on a lighter foundation.
How we build fast websites
Every website we build is hand-coded without bloated page builders, with optimised responsive images, self-hosted fonts and minimal JavaScript. That means fast loading and strong Core Web Vitals from day one. If your current site is slow, our website speed optimisation service can help, or request a free website review to see how you’re doing.
