PageSpeed monitoring
Core Web Vitals explained
LCP, FCP, CLS, TBT, and Speed Index.
Overview
Core Web Vitals are Google's key metrics for measuring user experience. Checkmate tracks these metrics to help you understand and improve page performance.
Largest Contentful Paint (LCP)
LCP measures how long it takes for the largest visible element to load. Target: under 2.5 seconds.
First Contentful Paint (FCP)
FCP measures when the first content appears on screen. Target: under 1.8 seconds.
Cumulative Layout Shift (CLS)
CLS measures visual stability—how much the page layout shifts during loading. Target: under 0.1.
Total Blocking Time (TBT)
TBT measures how long the page is unresponsive to user input. Target: under 200 milliseconds.
Speed Index
Speed Index measures how quickly content is visually displayed. Target: under 3.4 seconds.