Core Web Vitals

Core Web Vitals are a set of user experience metrics defined by Google that measure how well a web page performs in terms of loading speed, interactivity, and visual stability. These metrics are important because they reflect the real-world experience of users when they visit your website.

Starting in 2021, Core Web Vitals became part of Google’s ranking algorithm as a component of the overall Page Experience update. This means that improving these metrics not only enhances user satisfaction but can also help your pages rank better in search results.

The three Core Web Vitals

1. Largest Contentful Paint (LCP) – Loading performance
   Measures how long it takes for the largest visible element (like an image or heading) to load.
   • Good: under 2.5 seconds
   • Measures: loading time
2. First Input Delay (FID) – Interactivity
   Measures how long it takes for the page to respond when a user first interacts (e.g., clicks a button or link).
   • Good: under 100 milliseconds
   • Measures: responsiveness
3. Cumulative Layout Shift (CLS) – Visual stability
   Measures how much the layout shifts as the page loads. Pages with unexpected movement are frustrating to users.
   • Good: less than 0.1
   • Measures: layout shift or jank

Note: As of 2024, Interaction to Next Paint (INP) is set to replace FID as a more comprehensive measure of interactivity.

Why Core Web Vitals matter for SEO

Core Web Vitals are part of Google’s Page Experience signals, which also include mobile-friendliness, HTTPS security, and lack of intrusive interstitials (popups).

Improving your Core Web Vitals can lead to:

• Higher search rankings
• Increased user satisfaction
• Lower bounce rates
• Better engagement and conversion rates

While Core Web Vitals are not the most important ranking factor, they can make a difference in competitive search environments, especially when content quality is similar between sites.

How to measure Core Web Vitals

You can check your site’s Core Web Vitals using:

• Google Search Console (Core Web Vitals report)
• PageSpeed Insights
• Lighthouse (built into Chrome DevTools)
• Web Vitals Chrome Extension
• CrUX (Chrome User Experience Report) – for real-world data

How to improve Core Web Vitals

• Optimize images and videos (compress, lazy load, use modern formats like WebP)
• Minimize JavaScript and CSS blocking resources
• Use a fast, reliable hosting provider and a Content Delivery Network (CDN)
• Reserve space for ads, embeds, and dynamic content to reduce layout shifts
• Optimize web fonts and avoid layout jank

In summary, Core Web Vitals are essential metrics that help you measure and improve how real users experience your website. They are part of Google’s ranking system and offer actionable insights into how to create faster, more responsive, and more stable websites.