Core Web Vitals Explained: LCP, CLS and INP

What Are Core Web Vitals?

Core Web Vitals are a set of metrics Google uses to evaluate real-world user experience. Since 2021 they are an official Google ranking signal. There are three you need to nail.

LCP – Largest Contentful Paint

LCP measures how long it takes for the largest visible element to load. Target: under 2.5 seconds. Fix it by optimising your hero image, removing render-blocking resources, and using a CDN.

CLS – Cumulative Layout Shift

CLS measures visual stability – how much the page layout shifts unexpectedly during load. Target: below 0.1. Fix it by always setting width and height on images and reserving space for ads.

INP – Interaction to Next Paint

INP replaced FID in 2024 and measures how responsive a page is to user interactions. Target: under 200 ms. Fix it by reducing long tasks, delaying third-party scripts, and avoiding heavy JS on load.

All three metrics are measured and improved automatically by PageSpeedBooster.