Core Web Vitals are Google’s way of measuring whether a page feels fast to a real person. There are three of them, and each has a plain-English meaning.
LCP: how long until the big thing appears
Largest Contentful Paint is the time until the main image or headline is on screen. Target: under 2.5 seconds. Usual fixes: compress and correctly size the hero image, serve it from a CDN, and stop render-blocking scripts from loading first.
INP: how quickly the page responds
Interaction to Next Paint measures the delay between a tap or click and the screen updating. Target: under 200 milliseconds. Usual culprits: heavy page-builder scripts, chat widgets and tracking tags all competing for the main thread.
CLS: does the layout jump
Cumulative Layout Shift catches content that moves while loading, like a banner pushing the text down. Target: under 0.1. Usual fixes: set image dimensions, reserve space for ads and embeds, and load fonts with a fallback.
Measure with real-user data in Search Console, not just a lab tool, and fix the worst template first. One template usually accounts for most of the traffic.