What are Core Web Vitals?
Core Web Vitals are three measurements Google uses to judge how good an experience your website gives visitors. Think of them as a health check on how fast, stable, and responsive your site feels when someone lands on it.
Google officially introduced Core Web Vitals as a ranking signal in May 2021, and they are now a confirmed part of how your site is scored in search results. You can find Google's own documentation on these metrics at web.dev/vitals, which is run by Google's developer team.
Why should a small business owner care?
If your website is slow or awkward to use, two bad things happen at once. Visitors leave before they have read a word, and Google notices and quietly pushes your site further down the search results.
For a bakery, a plumber, or a boutique clothing shop, your website is often the first impression a potential customer gets. A poor experience there costs you real sales, not just clicks.
You do not need a big budget or a technical background to improve your Core Web Vitals scores. Most small business websites have a handful of common problems that are straightforward to fix once you know what they are.
The three Core Web Vitals explained
Each metric measures a different part of the user experience. Here is what each one means in plain language.
1. Largest Contentful Paint (LCP) — how fast does your page load?
LCP measures how long it takes for the biggest visible element on your page to appear on screen. That is usually your main photo, your logo, or a large block of text.
Imagine walking into a shop where the lights take five seconds to come on. By the time they do, half the customers have turned around and left. LCP is that exact moment.
| LCP Score | What It Means |
|---|---|
| Under 2.5 seconds | Good — Google is happy |
| 2.5 to 4 seconds | Needs improvement |
| Over 4 seconds | Poor — this will hurt your rankings |
Common causes of a slow LCP:
- Large, uncompressed images (a photo straight from your phone, for example)
- A slow web hosting provider
- Too many unnecessary add-ons or plugins loading in the background
2. Interaction to Next Paint (INP) — does your page respond quickly?
INP measures how quickly your page reacts when a visitor does something: clicking a button, tapping a menu, or filling in a contact form. A slow INP makes your site feel sluggish, like a touchscreen that takes a moment to register your tap.
Google replaced an older measurement called First Input Delay (FID) with INP in March 2024, making it a stricter and more accurate test of responsiveness.
| INP Score | What It Means |
|---|---|
| Under 200 milliseconds | Good |
| 200 to 500 milliseconds | Needs improvement |
| Over 500 milliseconds | Poor |
Common causes of a slow INP:
- Overloaded JavaScript (sets of instructions your browser has to run in the background)
- Too many third-party tools running at once, such as live chat widgets, cookie banners, and ad scripts
3. Cumulative Layout Shift (CLS) — does your page jump around?
CLS measures how much the content on your page moves while it is loading. You have almost certainly experienced this: you go to tap a button and the page shifts at the last second, so you end up clicking something you did not mean to.
That is a layout shift, and it is one of the most frustrating things a visitor can encounter on a website.
| CLS Score | What It Means |
|---|---|
| Under 0.1 | Good |
| 0.1 to 0.25 | Needs improvement |
| Over 0.25 | Poor |
Common causes of a high CLS score:
- Images without defined dimensions (so the browser does not know how much space to reserve for them)
- Adverts or cookie banners that load late and push the rest of the content down
- Fonts that swap in after the page has already started displaying
How does Google actually use these scores?
Google uses Core Web Vitals as part of what it calls its Page Experience signals. These are a collection of factors that together tell Google whether your page is a decent place to visit.
The scores come from real visitors using Chrome browsers, not automated tests. Google calls this real-world data the Chrome User Experience Report (CrUX). That matters because Google is judging your site based on how actual people experience it, not a test run under perfect conditions.
If you are wondering why your site is not appearing where you expect in search results, slow Core Web Vitals scores could be part of the reason. Our guide on why your website might not be showing up on Google covers several other factors worth checking at the same time.
How to check your own Core Web Vitals
You do not need to hire a developer just to find out your scores. Several free tools will show you exactly where you stand.
Free tools you can use right now:
- Google PageSpeed Insights — Go to pagespeed.web.dev, type in your website address, and it will give you scores for both mobile and desktop visitors.
- Google Search Console — Google's free dashboard for website owners has a dedicated Core Web Vitals report showing your real-world scores over time. If you have not set it up yet, our guide to what Google Search Console is and how to use it will walk you through it step by step.
- AuditMy Free Check — Run a free check at website.auditmy.co.uk, which flags Core Web Vitals problems alongside other common issues in one simple report.
💡 Start with the mobile scores rather than the desktop ones. Most of your customers are visiting on their phones, and Google primarily judges your site based on the mobile experience.
What can you actually do to improve?
The fixes depend on what platform your website is built on. Here are the most common starting points.
WordPress
Install a caching plugin (a tool that saves a ready-made version of your pages so they load faster) such as WP Super Cache or W3 Total Cache. Also install a plugin like Smush or ShortPixel to compress your images automatically without reducing their quality.
Shopify
Shopify handles a lot of the heavy lifting for you, but themes and apps are often the culprit. Try switching to a leaner theme and removing any apps you are not actively using. Each app you add loads extra code on every page.
Squarespace or Wix
These platforms update performance automatically, so your main job is keeping images small before you upload them. Aim for file sizes under 200KB where possible. Free tools like Squoosh (squoosh.app) let you compress images in your browser before uploading.
⚠️ Be cautious about installing lots of plugins or apps in the hope that they will fix things. Too many performance tools can actually slow your site down further if they conflict with each other.
A quick summary
| Core Web Vital | What It Measures | Good Score |
|---|---|---|
| Largest Contentful Paint (LCP) | How fast your page loads | Under 2.5 seconds |
| Interaction to Next Paint (INP) | How quickly your page responds to clicks | Under 200ms |
| Cumulative Layout Shift (CLS) | How much your page jumps around | Under 0.1 |
Better scores will not just keep Google happy. A faster, more stable website means more people will stick around long enough to contact you, book a table, or place an order.
💡 Once you have sorted your Core Web Vitals, it is worth having a look at what meta descriptions are and why they matter. They are another small thing that costs nothing to fix and can make a real difference to how many people click through to your site from search results.
Start with a free check, find out what your biggest issue is, and tackle one thing at a time. You do not need to fix everything in a weekend. Small, consistent improvements add up.
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