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PageSpeed, Core Web Vitals & Lighthouse Scores – for better rankings and AI visibility
Enter URL — Mobile and Desktop are tested simultaneously
A Website Performance Check measures how fast and stable your page loads — and is far more than a classic SEO tool. Core Web Vitals are Google's three key metrics: LCP (Largest Contentful Paint) measures main content load time, CLS (Cumulative Layout Shift) evaluates visual stability and INP (Interaction to Next Paint) measures responsiveness. Since 2021 they are an official Google ranking factor.
The Lighthouse Score summarizes Performance, Accessibility, Best Practices and SEO in a single number from 0–100. Scores above 90 are considered good. Mobile scores are almost always lower than desktop — Google simulates a slower device with a throttled connection.
TBT (Total Blocking Time) measures how long the main thread is blocked. A high TBT is often a sign of too much JavaScript — the most common cause of poor mobile scores.
Performance also matters for AI visibility: Crawlers from ChatGPT, Perplexity and Claude have shorter timeouts than Googlebot. A high TTFB or blocking resources can prevent your content from being crawled by AI systems — and therefore not cited in AI answers.
Core Web Vitals are three metrics defined by Google: LCP (load time of the largest visible element), CLS (visual stability during loading) and INP (response time to user input). Since 2021 they are an official ranking factor — poor values can reduce visibility in search results.
Google rates scores 90–100 as good (green), 50–89 as needs improvement (orange) and below 50 as poor (red). Requirements for mobile are stricter than for desktop. A score above 90 on mobile is considered very good and is hard to achieve for most websites.
LCP (Largest Contentful Paint) measures how long it takes for the largest visible element to load — usually a hero image or heading. Good: under 2.5 seconds. Needs improvement: 2.5–4 seconds. Poor: over 4 seconds.
CLS (Cumulative Layout Shift) measures how much elements shift during loading. Good: under 0.1. Common causes are images without defined sizes, late-loaded ads or web fonts that trigger layout shifts. Explicit width/height attributes on images often fix this immediately.
Lighthouse simulates a slower device (Moto G4) with throttled CPU and 4G connection for mobile. Desktop tests run without throttling. Mobile scores are therefore almost always significantly lower — this is normal since Google primarily indexes mobile-first.