Google measures three things to judge how a real visitor experiences your page: how fast the main content loads, how stable the layout is while it loads, and how quickly the page responds to clicks and taps. Together, these are called Core Web Vitals.
LCP — Largest Contentful Paint
This measures how long it takes for the biggest visible element (often a hero image or heading) to render. Aim for under 2.5 seconds. The biggest wins here are usually optimizing images, removing render-blocking scripts, and using a CDN.
CLS — Cumulative Layout Shift
CLS measures how much content jumps around as the page loads — think of text shifting down when an ad or image suddenly appears. This is one of the most common (and most fixable) issues we see.
- Always set width and height (or aspect-ratio) on images and embeds so space is reserved before they load.
- Avoid injecting banners, popups, or ads above existing content without reserved space.
- Use font-display strategies that don't cause text to reflow once custom fonts load.
Reserved layout space for every element keeps the page stable as it loads — zero layout shift.
INP — Interaction to Next Paint
INP measures how quickly the page responds after a user clicks, taps, or types. Heavy JavaScript, large bundles, and unoptimized third-party scripts are the usual culprits. Code-splitting and lazy-loading non-critical scripts go a long way here.
Why this matters beyond rankings
Every extra second of load time is a chance for a visitor to bounce before they ever see your offer.
Core Web Vitals aren't just an SEO checkbox — a faster, more stable site directly improves conversion rates, especially on mobile. When we rebuild or audit a site, performance is one of the first things we measure, because it affects every other goal: traffic, trust, and sales.
