Core Web Vitals Audit

Test your website's Core Web Vitals using Google PageSpeed Insights. Get real-world performance data for LCP, INP, and CLS metrics that impact your Google rankings.

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LCP - Loading

Measures how fast your largest content element loads. Good: ≤2.5s

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INP - Interactivity

Measures responsiveness to user interactions. Good: ≤200ms

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CLS - Stability

Measures visual stability during page load. Good: ≤0.1

What Are Core Web Vitals?

Core Web Vitals are a set of real-world user experience metrics that Google uses as ranking signals. Since the Page Experience update, these metrics directly influence your search rankings and visibility.

Our tool uses Google PageSpeed Insights API (free) to analyze your website's performance on mobile devices. You'll get lab data from Lighthouse and, when available, field data from real Chrome users (Chrome User Experience Report).

The three Core Web Vitals are: LCP (loading performance), INP (interactivity - replaced FID in 2024), and CLS (visual stability). Optimizing these metrics improves user experience and can boost your Google rankings.

Why Core Web Vitals Matter

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Google Ranking Factor

Core Web Vitals are confirmed Google ranking signals. Pages with good vitals rank higher in search results, especially on mobile.

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Better User Experience

Fast, responsive, stable pages keep visitors engaged. Poor vitals lead to frustration, bounces, and lost conversions.

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Higher Conversions

Studies show that improving LCP from 3.5s to 1.7s can increase conversion rates by 11%. Speed = revenue.

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Mobile-First Indexing

Google primarily uses mobile performance for ranking. Our tool tests mobile vitals to match Google's criteria.

Frequently Asked Questions

What is LCP and what's a good score?

LCP (Largest Contentful Paint) measures how long it takes for the largest visible element to load. Good: ≤2.5 seconds, Needs Improvement: 2.5-4.0s, Poor: >4.0s. To improve: optimize images, improve server response time, remove render-blocking resources.

What is INP and how is it different from FID?

INP (Interaction to Next Paint) replaced FID in March 2024. It measures the delay between user interactions and visual updates. Good: ≤200ms, Needs Improvement: 200-500ms, Poor: >500ms. INP is more comprehensive than FID as it measures all interactions, not just the first one.

What is CLS and why does my page shift?

CLS (Cumulative Layout Shift) measures visual stability. Good: ≤0.1, Needs Improvement: 0.1-0.25, Poor: >0.25. Common causes: images without dimensions, ads, web fonts, dynamically injected content. Fix by setting explicit width/height on images and reserving space for ads.

Do Core Web Vitals affect SEO rankings?

Yes! Core Web Vitals are confirmed Google ranking factors since the Page Experience update. While content quality is still most important, good vitals can give you a ranking boost, especially when competing pages have similar content quality.

What's the difference between lab data and field data?

Lab data comes from Lighthouse testing in controlled conditions. Field data comes from real Chrome users (Chrome User Experience Report). Field data is more accurate for SEO as it reflects real-world performance, but requires sufficient traffic. Our tool shows both when available.

How often should I test Core Web Vitals?

Test after making significant changes to your site, or at least monthly. Also monitor Google Search Console's Core Web Vitals report for field data trends. Regular testing helps you catch issues before they impact rankings.