Updated April 18, 2026

What are Core Web Vitals?

Core Web Vitals are three Google performance metrics: Largest Contentful Paint (LCP, loading speed), Interaction to Next Paint (INP, responsiveness, replaced FID in March 2024), and Cumulative Layout Shift (CLS, visual stability). All three are confirmed mobile-search ranking signals. Pages that hit "Good" on all three earn a small but real boost.

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Why Google made these the standard

Google introduced Core Web Vitals in 2020 as a unified, measurable definition of "page experience." Before, "fast" was subjective. Now there are three numbers any page can be measured against, both in lab (Lighthouse) and field (Chrome User Experience Report) data. Google explicitly uses the field data as a ranking signal in mobile search.

How to read each metric

LCP: when the largest visible element renders. Long LCP usually means a slow hero image or render-blocking JS. INP: how long the page takes to respond to a click or tap. Long INP usually means heavy JavaScript, especially third-party scripts. CLS: how much the page jumps around while loading. High CLS usually means images without explicit dimensions, or late-loading ads/embeds.

What "Good" actually requires

To pass Core Web Vitals: 75% of visits to a page must hit Good thresholds on all three metrics. The 75th percentile is harsh — your average user can be fast while you still fail because the slowest 25% miss. Run your page through PageSpeed to see your real-user data.

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Related questions

What is Largest Contentful Paint (LCP)?

Largest Contentful Paint (LCP) is the moment the biggest visible element above the fold finishes rendering — usually the hero image, hero video poster, or a large headline block. Google's threshold for "good" LCP is under 2.5 seconds. LCP is one of three Core Web Vitals and a confirmed ranking signal in mobile search.

What is the ideal landing page load time?

Aim for Largest Contentful Paint (LCP) under 2.5 seconds and Interaction to Next Paint (INP) under 200ms. Google's data shows each additional second of load time increases bounce probability by ~32%. Pages above 3 seconds typically lose 25–40% of mobile visitors before render. Page-speed gains compound — a faster page also ranks higher in Google.

Does page speed affect conversion rates?

Yes, dramatically. Each additional second of load time increases bounce probability by ~32% (Google), and conversion rates drop 7% per second saved on LCP (Akamai). The effect compounds on mobile, where slow connections amplify every wasted millisecond. Pages above 4 seconds typically lose 40–60% of mobile visitors before they ever see the content.

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