What are Core Web Vitals? (CWV)
Core Web Vitals are Google's metrics measuring page loading, interactivity, and visual stability. Learn how CWV affects SEO and user experience.
Core Web Vitals are a specific set of user experience measurements that Google uses as ranking signals. The three metrics - Largest Contentful Paint (LCP), Interaction to Next Paint (INP), and Cumulative Layout Shift (CLS) - quantify what users actually experience when visiting your pages. Passing thresholds on all three earns you a 'good' page experience score.
Why it matters
Core Web Vitals matter because they quantify what users feel. A page that takes 5 seconds to load or shifts around as users try to click isn't just annoying - it drives people away. Studies consistently show that conversion rates drop significantly as page load times increase. For marketers, CWV provides a common language to communicate with developers. Instead of saying 'the page feels slow,' you can point to specific metrics with specific thresholds. This makes prioritization and progress tracking concrete. The SEO benefit is real but secondary: the primary value is keeping users engaged long enough to convert.
What people get wrong
- Passing Core Web Vitals will dramatically boost your rankings. CWV is a tiebreaker, not a primary ranking factor. Google has explicitly stated that content quality matters more. Sites with poor CWV but great content regularly outrank sites with perfect scores but thin content.
- Lighthouse scores and Core Web Vitals are the same thing. Lighthouse runs lab tests in controlled conditions. Core Web Vitals use field data from real Chrome users. A page can score 100 in Lighthouse while failing CWV because actual visitors have slower devices or connections.
- You need to optimize every page on your site. Google evaluates pages individually, and not all pages carry equal weight. Focus on high-traffic, high-value pages first. A failing 404 page or internal utility page rarely impacts your overall SEO performance.
Related terms
Technical SEO: Core Web Vitals fall under technical SEO, which covers all infrastructure optimizations that affect how search engines crawl, index, and rank your site.
SEO: CWV is one ranking signal within Google's broader search algorithm. Strong overall SEO requires both technical performance and content quality.
User Intent: Understanding user intent guides what content to create, while Core Web Vitals ensure users can actually access and interact with that content effectively.
Frequently Asked Questions
What are Core Web Vitals?
Core Web Vitals are three Google metrics that measure page experience: Largest Contentful Paint (loading speed), Interaction to Next Paint (responsiveness), and Cumulative Layout Shift (visual stability). Google uses field data from Chrome users to score pages and uses these scores as a ranking signal.
What are the passing thresholds for Core Web Vitals?
LCP should be 2.5 seconds or less, INP should be 200 milliseconds or less, and CLS should be 0.1 or less. Meeting all three thresholds at the 75th percentile of your visitors gives you a 'good' rating. Between thresholds is 'needs improvement,' and beyond is 'poor.'
How do I check my Core Web Vitals scores?
Google Search Console provides CWV data for your entire site. PageSpeed Insights shows scores for individual URLs along with specific recommendations. Chrome DevTools and Lighthouse offer lab testing. The CrUX Dashboard provides historical trends and comparisons.
What happened to First Input Delay (FID)?
Google replaced FID with Interaction to Next Paint (INP) in March 2024. FID only measured the delay before the first interaction was processed. INP measures responsiveness throughout the entire page session, capturing all interactions and reporting based on the worst ones.
Do Core Web Vitals affect mobile and desktop rankings differently?
Google measures and reports CWV separately for mobile and desktop, and scores often differ significantly. Since Google primarily uses mobile-first indexing, mobile CWV scores typically matter more for rankings. Most sites see worse mobile scores due to slower processors and variable network conditions.