Google’s Core Web Vitals have been a ranking signal since 2021, yet most websites we audit still have significant issues. Here’s a plain-English breakdown of what each metric measures and, more importantly, how to fix the most common problems.
The Three Metrics
Largest Contentful Paint (LCP)
LCP measures how long it takes for the largest visible element on the page — usually a hero image or headline — to fully load. Google considers anything under 2.5 seconds “good.” Above 4 seconds is “poor.”
The most common culprits: unoptimized hero images, slow server response times, and render-blocking JavaScript.
- Convert images to WebP or AVIF format
- Use a CDN to serve assets closer to the user
- Add
loading="lazy"to below-fold images (but never to the hero) - Preload your LCP image with a
<link rel="preload">tag
Interaction to Next Paint (INP)
INP replaced First Input Delay in 2024. It measures the responsiveness of your page to user interactions throughout the entire page lifecycle, not just the first interaction. Good INP is under 200ms.
Heavy JavaScript is usually the culprit. Third-party scripts — analytics, chat widgets, ad tags — are often the biggest offenders.
Cumulative Layout Shift (CLS)
CLS measures visual stability. Have you ever been about to click a button and the page suddenly jumped, causing you to click something else? That’s a CLS problem. Good CLS is under 0.1.
The most common CLS cause we encounter: images and embeds without explicit width and height attributes. Add them, and you’ll often fix CLS in minutes.
How to Measure Your Vitals
- Google Search Console shows aggregate field data for your real users
- PageSpeed Insights gives both lab and field data for individual URLs
- Chrome DevTools’ Performance tab shows a detailed breakdown
Do Vitals Actually Affect Rankings?
Yes, but as a tiebreaker rather than a primary signal. Two pages with similar content and authority — the one with better Vitals will generally rank higher. More practically, better Vitals mean lower bounce rates and higher engagement, which influence rankings through user behaviour signals.