What Core Web Vitals actually measure
Core Web Vitals are three metrics Google uses to score real-world page experience. Largest Contentful Paint (LCP) measures how quickly the main content loads. Cumulative Layout Shift (CLS) measures how much the page jumps around as it loads. Interaction to Next Paint (INP) measures how quickly the page responds when someone taps or clicks.
They are a ranking factor, and more importantly they decide whether a visitor stays. A page that loads slowly or jumps around loses customers before they read a word.
Fix LCP: tame your biggest image
On most small business pages the LCP element is the hero image. Serve it in a modern format, size it to the space it actually fills rather than uploading a huge original, and load it with priority so the browser fetches it first. This single change clears most failing LCP scores.
Fix CLS: reserve the space
Layout shift happens when something loads and pushes content down: an image with no dimensions, an ad slot, a late-loading font. Set explicit width and height on every image, reserve space for embeds, and load fonts in a way that does not reflow the page. Reserving space is usually a small code change with an outsized result.
Fix INP: ship less JavaScript
Sluggish response usually comes from too much JavaScript running on the main thread. Remove scripts you do not need, defer the ones you do, and avoid heavy third-party widgets that block interaction. Fewer, lighter scripts make taps feel instant.
Measure with real data
Lab tools are useful for diagnosis, but Google ranks on field data from real visitors. Check your scores in a tool that reports field data, fix the worst page first, and re-measure. Chasing a perfect lab score while real users still struggle is wasted effort.