Digital marketing glossary

What are Core Web Vitals?

Written and reviewed by L.K. Monu Borkala · Updated 10 November 2026

Definition

Core Web Vitals are three measurements Google uses to judge the experience of loading and using a web page: Largest Contentful Paint (LCP) for loading speed, Interaction to Next Paint (INP) for responsiveness, and Cumulative Layout Shift (CLS) for visual stability. They are part of Google's page experience signals.

How it works

Google's guidance for a good experience is an LCP of 2.5 seconds or less, an INP of 200 milliseconds or less, and a CLS of 0.1 or less, measured at the 75th percentile of real visits on mobile and desktop. The data comes from real Chrome users, so it reflects visitors' actual phones and networks, not just a lab test. You can see your site's results in Google Search Console's Core Web Vitals report and in PageSpeed Insights. Common fixes include compressing and correctly sizing images, reserving space for images and ads so content doesn't jump, loading fewer third-party scripts, and using good hosting or a CDN. Better vitals help users, but relevant, helpful content still matters more for ranking.

Example

Picture a recipe blog from Hyderabad whose pages jump around as ads load, so readers tap the wrong link. PageSpeed Insights shows a CLS of 0.35 and an LCP of 4.8 seconds on mobile. The owner sets fixed sizes for ad slots and images, converts photos to WebP and removes two unused plugins. A month later, real-user data shows CLS under 0.1 and LCP around 2.3 seconds, and visitors read more pages.

An illustration: the business and the rupee figures are made up to show how the idea works.

Common mistake

Optimising only for a perfect lab score on a fast office laptop. Core Web Vitals are judged on real users, often on mid-range phones and mobile data in India, so test on those conditions too.