What Are Core Web Vitals? A Simple Guide for Business Owners
Google uses three specific measurements to judge your website's user experience. Here's what they are, why they matter, and how to improve them — no technical background needed.
What Google Measures
Core Web Vitals are three metrics that Google uses to measure how your website feels to real visitors. Since 2021, these scores directly affect where your site appears in search results. A site with good Core Web Vitals will rank higher than an identical site with poor scores.
The Three Metrics
LCP — Largest Contentful Paint
What it measures: How long it takes for the main content on your page to appear. This is usually the hero image, main heading, or largest text block.
In plain English: How quickly does your page look "loaded" to the visitor?
Good: under 2.5 seconds | Needs work: 2.5–4 seconds | Poor: over 4 seconds
INP — Interaction to Next Paint
What it measures: How quickly your page responds when someone clicks a button, taps a link, or types in a form. INP replaced the older FID (First Input Delay) metric in March 2024.
In plain English: When a visitor clicks something, does the page react instantly or does it feel sluggish?
Good: under 200ms | Needs work: 200–500ms | Poor: over 500ms
CLS — Cumulative Layout Shift
What it measures: How much the page content moves around as it loads. Have you ever tried to click a button, but the page shifted and you clicked something else? That's layout shift.
In plain English: Does the page stay still while loading, or does everything jump around?
Good: under 0.1 | Needs work: 0.1–0.25 | Poor: over 0.25
Why It Matters for Your Business
Google uses Core Web Vitals as a ranking factor. If two websites have similar content and SEO, the one with better Core Web Vitals will rank higher. But it's not just about Google — these metrics directly correlate with conversions:
- • A 100ms improvement in LCP increases conversions by up to 8%
- • Pages with good CLS have 24% lower bounce rates
- • Slow INP makes forms and checkout feel broken — visitors give up
How to Check Your Scores
You can check your Core Web Vitals using Google PageSpeed Insights, Chrome DevTools, or Google Search Console. The challenge is that these tools give you raw numbers and technical jargon. Unless you know what "reduce unused JavaScript" means in practice, the recommendations aren't actionable.
AuditStack translates your PageSpeed results into plain-English recommendations — what each issue means, why it matters, and exactly how to fix it.
How to Improve Your Scores
Improve LCP
Optimise your largest image (compress it, use WebP format, add width/height attributes). Use a CDN to serve files from servers close to your visitors. Minimise render-blocking CSS and JavaScript.
Improve INP
Reduce the amount of JavaScript on your page. Break up long-running scripts into smaller chunks. Remove third-party scripts you're not actively using (old analytics, unused chat widgets).
Improve CLS
Always set width and height on images and videos. Reserve space for ads and dynamic content before they load. Avoid inserting content above existing content after the page has started rendering.
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