Core Web Vitals: the three numbers that move conversion

Key takeaway

Core Web Vitals are three numbers Google weights and users feel: LCP (how fast the main content appears), INP (how quickly the page responds to a tap), and CLS (how much the layout jumps while loading). Fix these three, measured on real phones and networks — not a hundred lab findings that don't move anything.

Performance work spirals easily — you can generate a hundred findings and fix none that matter. Core Web Vitals gives you three numbers that both search engines weight and users actually feel. Start there.

The three that matter

LCP (Largest Contentful Paint) — how fast the main content shows. Usually your hero image or headline.
INP (Interaction to Next Paint) — how quickly the page responds when someone taps or clicks.
CLS (Cumulative Layout Shift) — how much the page jumps around while loading.

Tip

Measure with field data, not just your laptop. Your dev machine on fast wifi hides the exact problems your users on mid-range phones are living with. Real-user metrics are the truth.

The usual culprits

LCP is often an unoptimized hero image or a slow server response. INP is usually too much JavaScript running on the main thread. CLS is images and embeds without reserved space.

The fix for that last one is unglamorous: give every image, video, and embed an explicit width and height — or otherwise reserve its space in the layout — so the browser holds the spot instead of letting the page lurch as things load.

Watch out

Chasing a perfect lab score while ignition-slow third-party scripts tank the real experience is a trap. Fix what field data shows real users hit, in order of impact.

We build performance-aware, accessible web experiences — fast where it counts, measured with real data, and maintainable so the numbers stay good after launch, not just on day one. Speed is only one lens, though: a real audit looks at the whole system — performance, accessibility, findability, and the CRM behind it.

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