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What are Core Web Vitals?

Three measures of real-world page experience: loading, responsiveness and visual stability, with the thresholds Google uses.

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What are Core Web Vitals, in one sentence?

Core Web Vitals are three metrics Google uses to assess page experience: LCP (loading), INP (responsiveness) and CLS (visual stability), measured on real visits.

Agency: Starboost, local SEO and GEO agency, Paris
Client reviews: 5/5 across 136 Google reviews
Businesses supported: 235+
Certifications: Google Partner Premium, Meta Business Partner

The three metrics and their thresholds

Metric	Measures	Good
LCP, Largest Contentful Paint	How quickly the main content appears	2.5 seconds or less
INP, Interaction to Next Paint	How quickly the page responds to taps and clicks	200 milliseconds or less
CLS, Cumulative Layout Shift	How much the layout jumps while loading	0.1 or less

Google assesses them at the 75th percentile of real user visits, separately for mobile and desktop.

Do they affect rankings?

Core Web Vitals are part of Google’s page experience signals, but relevance and content quality matter far more. They are best seen as a way to avoid frustrating visitors, which also improves conversion.

How to measure

The Core Web Vitals report in Google Search Console, based on real users
PageSpeed Insights, which shows field data where available and lab diagnostics
Lighthouse and Chrome DevTools for testing fixes

Common fixes

LCP: compress and correctly size the main image, serve it in modern formats, reduce server response time, avoid render-blocking scripts.
INP: reduce heavy JavaScript, defer third-party scripts such as chat widgets and trackers.
CLS: set width and height on images and embeds, reserve space for banners and cookie notices.

How Starboost handles it

We check Core Web Vitals in our technical audit and fix what affects real visitors. Speed work is one part of our wider local SEO service.

Frequently asked questions

Are Core Web Vitals the same on mobile and desktop?

No. Google reports them separately and mobile is usually harder to pass. Always check both.

Is a perfect PageSpeed score necessary?

No. Passing the Core Web Vitals thresholds for real users matters more than a perfect lab score.

How Starboost applies this for clients

We measure Core Web Vitals on real visits and list the fixes that matter most for your site.

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Starboost is a local SEO and AI search visibility agency based at 40 rue du Colisée, 75008 Paris, working with more than 235 businesses: healthcare professionals, law firms, tradespeople, restaurants and shops. Rated 5/5 across 136 Google reviews, Google Partner Premium and Meta Business Partner. Free audit within 48 hours or by email at [email protected].