Definition
Core Web Vitals are a set of real-world user experience metrics defined by Google that measure how users experience the speed, responsiveness, and visual stability of a web page. Introduced as part of Google's Page Experience signals, these metrics became official ranking factors in 2021. The three current Core Web Vitals are Largest Contentful Paint (LCP) which measures loading performance, First Input Delay (FID) which measures interactivity, and Cumulative Layout Shift (CLS) which measures visual stability. These metrics are designed to capture the most important aspects of user experience that affect how users perceive a website's performance and usability.
Common Misconceptions
“Core Web Vitals only matter for Google rankings”
While Google uses them as ranking factors, Core Web Vitals primarily measure real user experience. Poor scores indicate actual usability problems that affect all users, regardless of how they find your site.
“Perfect scores are required for good SEO”
Google uses thresholds (Good, Needs Improvement, Poor) rather than requiring perfect scores. The goal is to provide a good user experience, not achieve perfect metrics.
“Core Web Vitals are the same as page speed”
Core Web Vitals measure specific aspects of user experience beyond just speed. Visual stability and interactivity are equally important and can’t be measured by traditional speed tests alone.
“Fixing Core Web Vitals is a one-time task”
Core Web Vitals require ongoing monitoring and optimization. New content, updates, and changing user behavior can impact scores over time.
“Mobile and desktop scores are equally important”
Google primarily uses mobile Core Web Vitals for ranking since most searches now happen on mobile devices. Mobile optimization should be the priority.
“Third-party scripts don’t affect Core Web Vitals”
Third-party scripts (ads, analytics, chat widgets) often significantly impact Core Web Vitals, especially FID and CLS. These need careful optimization and monitoring.
References & Resources
Comprehensive guides and best practices from Google:
Official SEO documentation including Core Web Vitals guidance:
Provides both lab and field data for Core Web Vitals:
Shows Core Web Vitals performance for your entire site:
Open-source auditing tool with Core Web Vitals measurement: