What are Core Web Vitals?

Core Web Vitals are the three metrics Google picked to measure real user experience. Since March 2024 the responsiveness metric is INP, not FID:

Google decides whether a page passes based on real-user (field) data, at the 75th percentile of visits. Lab measurements from tools like Lighthouse are for finding problems and testing fixes.

#Why it matters

• Core Web Vitals are part of Google's page experience signals. Their effect is smaller than content relevance, but they can make a difference between otherwise similar pages.
• More importantly, visitors care: a page that loads slowly, jumps around or reacts late gets abandoned and converts worse.

#Where you see it in SEOAsist

• The Core Web Vitals card on the Overview page shows PageSpeed Insights results for Mobile and Desktop: LCP, INP / TBT, CLS and the performance score. Markers on the bars show the good and poor thresholds. Biggest wins (mobile) lists PageSpeed's top suggestions.
• Measure queues a mobile and desktop measurement of the home page and top-impression pages. The same card also appears on the site page's General tab.
• The Performance dimension in SEO analysis (mobile-weighted) turns threshold breaches into findings.

More: Overview dashboard, SEO analysis.

#Common mistakes

• Looking only at desktop results; Google uses mobile-first indexing.
• Treating the Lighthouse performance score as the same thing as passing Core Web Vitals.
• Optimising only the home page, while traffic mostly lands on product and blog pages.
• Still judging pages by FID; it is no longer a Core Web Vital.