"Core Web Vitals: Google's Site-Speed Criteria"

Google rewards a "fast" site, but what does "fast" mean? The answer is in Core Web Vitals: three concrete metrics measure the performance of the user experience. These metrics are now a ranking signal; there's no avoiding them.

01. LCP (Largest Contentful Paint)

When the largest visual element on the page appears. Target: under 2.5 seconds. Improvement:

• Serving images in next-gen formats (WebP, AVIF)
• Loading critical CSS inline
• Not lazy-loading the hero image
• Using a CDN

02. INP (Interaction to Next Paint)

It replaced FID in 2024. How quickly the site responds to user interaction. Target: under 200 ms. Improvement:

• Splitting heavy JavaScript with code-splitting
• Deferring third-party scripts
• Using a Web Worker

03. CLS (Cumulative Layout Shift)

The amount elements shift while the page loads. Target: under 0.1. Improvement:

• Width/height must be specified for images
• Font FOIT/FOUT should be prevented
• Dynamic ad slots should be reserved in advance

04. Measurement Tools

Standard tools for measuring Core Web Vitals:

• Google PageSpeed Insights
• Chrome DevTools Lighthouse
• Google Search Console (real-user data)
• Chrome UX Report (CrUX)

The test-environment score can differ from the real-user score; decisions should be made by looking at real-user data.