Core Web Vitals are three field metrics Google uses to quantify real-world page experience. They measure how fast a page shows content, how quickly it responds to input, and how stable the layout is as it loads.
The three metrics
- Largest Contentful Paint (LCP) measures loading. It marks when the largest visible element renders. Aim for under 2.5 seconds.
- Interaction to Next Paint (INP) measures responsiveness. It captures the delay between a user action and the visual response. Aim for under 200 milliseconds. INP replaced First Input Delay in 2024.
- Cumulative Layout Shift (CLS) measures visual stability, the amount elements jump around during load. Aim for under 0.1.
Why they matter
Google confirmed Core Web Vitals as a ranking signal as part of page experience. They are rarely the deciding factor against strong, relevant content, but they act as a tiebreaker and a floor. A page that frustrates users with slow loads and shifting layouts struggles to hold rankings against a faster competitor.
The data Google uses comes from real Chrome users (field data), not just lab tests. You can monitor it in Google Search Console and PageSpeed Insights.
How to improve them
Compress and correctly size images, defer non-critical scripts, reserve space for images and ads to prevent shifts, and minimize heavy third-party code. These fixes also help AI crawlers reach and parse content efficiently, which supports citation eligibility.