Core Web Vitals sound technical, but they're really just three measures of whether your website feels good to use. Google uses them as a ranking signal, and — more importantly — they line up closely with whether visitors stick around. Here's each one in human terms.
LCP — does it load quickly?
Largest Contentful Paint measures how long it takes for the main content of a page to appear. If your hero image and headline take four seconds to show up, that's your LCP, and it's too slow. Aim for under 2.5 seconds. The usual culprits are oversized images, slow hosting and render-blocking scripts.
INP — does it respond quickly?
Interaction to Next Paint measures how snappily the page reacts when someone taps or clicks. A button that feels laggy erodes trust instantly. Heavy JavaScript is almost always to blame — the browser is too busy to respond. Shipping less script, and doing less work on the main thread, is the fix.
CLS — does it stay still?
Cumulative Layout Shift measures unexpected movement. You've felt this: you go to tap a link, an ad or image loads late, everything jumps, and you tap the wrong thing. Reserving space for images and embeds with explicit dimensions keeps the layout stable.
Why it's worth caring
Two reasons. First, these metrics feed into search rankings, so poor scores can quietly cost you visibility. Second, and bigger, speed correlates with money. Faster pages keep more visitors, and more visitors mean more enquiries and sales. We've seen a one-second improvement move conversion rates by double digits.
How we keep sites fast
- Right-sized, modern image formats (WebP) with explicit dimensions.
- Minimal, deferred JavaScript — no framework where plain code will do.
- System and web fonts loaded without blocking rendering.
- Lean, hand-written CSS instead of heavy utility bundles.
- Fast hosting and sensible caching.
None of this is exotic. It's discipline applied consistently — and it's why the sites we build tend to load in under two seconds and score in the green. If your website feels sluggish, the good news is that speed is almost always fixable.