Methodology

Data Collection

We measure 210,902 websites with Chrome field data. New crawls are added continuously; the data runs up to October 30, 2026.

Core Web Vitals (Field Data)

Core Web Vitals metrics (LCP, INP, CLS) come from the Chrome User Experience Report (CrUX) — real user data collected from Chrome users who have opted into sharing usage statistics. This is the same data Google uses for search ranking signals.

We report the 75th percentile (p75) for each metric, which is the standard threshold Google uses to determine if a site passes Core Web Vitals.

Lab Data

Additional metrics like Total Blocking Time (TBT), long task counts, DOM size, and resource loading patterns come from automated Lighthouse analysis of each site's homepage.

Technology Detection

CMS and framework detection is based on HTML source analysis, JavaScript library fingerprinting, and HTTP header inspection during the crawl.

Third-Party Analysis

Third-party providers (tag managers, analytics, consent platforms) are identified by matching requested domains and script signatures against a maintained database of known providers.

Metric Definitions

LCP (Largest Contentful Paint)

Time until the largest content element (image, text block, or video) is rendered. Good: ≤ 2,500ms. Poor: > 4,000ms.

INP (Interaction to Next Paint)

Responsiveness to user interactions (clicks, taps, key presses). Good: ≤ 200ms. Poor: > 500ms.

CLS (Cumulative Layout Shift)

Sum of unexpected layout shift scores during the page lifetime. Good: ≤ 0.1. Poor: > 0.25.

TBT (Total Blocking Time)

Sum of time beyond 50ms for each long task during page load. A lab proxy for interactivity.

Sample Bias

Our dataset skews toward larger, more popular websites. Sites that are not indexed by Chrome UX Report (low-traffic sites) are underrepresented. The results should be interpreted as representative of the “visible web” rather than the web as a whole.