Core Web Vitals Explained: LCP, INP and CLS in Plain English
Core Web Vitals are three measures of how a page feels to use. Largest Contentful Paint is how quickly the main content appears, with 2.5 seconds or less rated good. Interaction to Next Paint is how fast the page responds to taps, with 200 milliseconds or less rated good. Cumulative Layout Shift is how much the page jumps, with 0.1 or less rated good.
Contents
- The three measures
- Why they matter
- How to check your scores
- How to improve each measure
- What to prioritise for a local business
- Frequently asked questions
- Sources
The three measures
| Measure | In plain words | Good | Needs improvement | Poor |
|---|---|---|---|---|
| Largest Contentful Paint (LCP) | How long until the biggest thing on the screen, such as a photo or heading, has loaded | 2.5 seconds or less | Up to 4 seconds | More than 4 seconds |
| Interaction to Next Paint (INP) | How quickly the page reacts when someone taps or clicks | 200 milliseconds or less | Up to 500 milliseconds | More than 500 milliseconds |
| Cumulative Layout Shift (CLS) | How much things move around while the page loads | 0.1 or less | Up to 0.25 | More than 0.25 |
These are Google’s published thresholds. Google judges a page on how real visitors experience it, so a page passes when the large majority of visits meet the good level for all three.
Why they matter
Slow, jumpy pages lose visitors before they read anything. Core Web Vitals have also been a confirmed Google ranking signal since June 2021, alongside many other factors, so they matter most when your competitors are otherwise close. Published pass rates differ widely between sources, from about a third of sites to about half, so we do not quote one figure. Check your own pages.
Want a second pair of eyes? Clariti Digital can review your setup and show you what to fix first.
How to check your scores
- PageSpeed Insights. Enter a page address at pagespeed.web.dev. It shows real-visitor data where enough exists, and a lab test for the page you entered.
- Google Search Console. If your site is verified, the Core Web Vitals report groups your pages as good, needs improvement or poor, based on real visits. It needs enough traffic to show data.
- Our guided check. Our website speed and mobile check rates the three figures against Google’s thresholds and adds a mobile checklist.
Real-visitor data and lab data
Real-visitor data (also called field data) is what actual visitors experienced over recent weeks. Lab data is a single test run in controlled conditions. Real-visitor data is what Google uses, while lab data helps you find and test fixes.
How to improve each measure
- LCP: compress and resize the main image, use fast hosting and caching, and avoid loading heavy scripts before the main content.
- INP: remove unneeded scripts and widgets, and avoid long tasks that block the page from reacting.
- CLS: set width and height on images and embeds, reserve space for banners and adverts, and avoid inserting content above what the visitor is reading.
Our guide to why a website is slow on mobile lists the most common causes and the order to fix them.
What to prioritise for a local business
Fix the pages that bring in enquiries first: your homepage, your main service pages and your contact page. Aim for good on all three measures there before polishing the rest. Speed helps, but it is only one part of a site that turns visitors into enquiries; see nine checks when a website gets no enquiries.
Frequently asked questions
What are Core Web Vitals?
Three measures Google uses for page experience: how fast the main content loads, how quickly the page responds to taps, and how stable the layout is while loading.
What is a good Core Web Vitals score?
A Largest Contentful Paint of 2.5 seconds or less, an Interaction to Next Paint of 200 milliseconds or less and a Cumulative Layout Shift of 0.1 or less.
Do Core Web Vitals affect my Google ranking?
They have been a confirmed ranking signal since June 2021, but they are one of many factors. Relevance still matters most.
Why is there no score for my site in Search Console?
The report needs enough real visits to show data. Low-traffic sites may see no data, and PageSpeed Insights may show only lab results.
What replaced First Input Delay?
Interaction to Next Paint replaced First Input Delay as the responsiveness measure. Check Google’s documentation for the current definition.
Sources
- Google, Web Vitals, checked 11 October 2026.
- Google, PageSpeed Insights, checked 11 October 2026.
- Colorlib, Site speed statistics, checked 11 October 2026.
- DesignRush, Website speed statistics, checked 11 October 2026.
- TechLion, Website speed and Core Web Vitals for small business owners, checked 11 October 2026.
Sam, Editor at Clariti Digital.
Related guides
- Why is my website slow on mobile: The common reasons a website is slow on phones and how to fix them.
- Website speed and mobile check: A guided check of speed and mobile use with Google's thresholds.
- Website not getting enquiries: Nine checks when visitors arrive but do not get in touch.
Need help with this?
Clariti Digital is a UK digital growth agency for established local businesses. We start with a diagnostic, then fix what holds back visibility, enquiries and trust. Call +44 7435 063827 or email sam@claritidigital.com.