What is Core Web Vitals?
Core Web Vitals are a set of specific, measurable factors that Google considers important in a webpage’s overall user experience. They are part of Google’s Page Experience signals and directly impact search rankings. There are three Core Web Vitals metrics: Largest Contentful Paint (LCP), Interaction to Next Paint (INP), and Cumulative Layout Shift (CLS).
Why It Matters
Google officially uses Core Web Vitals as a ranking factor. Pages with poor scores are penalized in rankings compared to similar pages with better scores. Beyond SEO, these metrics directly affect user experience — slow or unstable pages cause visitors to leave.
How It Works
LCP measures loading performance — how long it takes for the largest visible content element (usually a hero image or headline) to appear. The target is under 2.5 seconds. INP measures responsiveness — how quickly a page responds to user interactions like button clicks. CLS measures visual stability — how much the layout shifts unexpectedly while loading. A low CLS means elements don’t jump around, preventing accidental clicks.
Real-World Example
A photography portfolio website has a beautiful hero image that takes 6 seconds to load. This poor LCP score is dragging down its rankings. After compressing images and enabling a CDN, LCP drops to 1.8 seconds, improving both user experience and search visibility.

