First Contentful Paint (FCP) is a timing-based metric that reports when the first content is rendered on screen. While FCP sounds similar to Largest Contentful Paint (LCP), but it’s not the same. FCP aims to measure when the first content appears, and LCP quantifies when the primary content appears.
Content, in FCP calculations, means:
In Calibre, FCP is sourced directly from Chrome browser. The browser emits this timing as part of it’s tracing.
|Good FCP Measurement||Poor FCP Measurement|
|≤ 1.8s||> 3s|