Largest Contentful Paint
A Core Web Vital measuring the render time of the largest image, video poster or text block visible in the viewport; good is 2.5 s or less…
TechnicalFCP
First Contentful Paint
The time from navigation start until the browser renders the first piece of DOM content; a diagnostic metric rather than a Core Web Vital.
In full
FCP marks the first visible feedback that something is loading — any text, image, canvas or SVG. web.dev treats 1.8 s or less as good. Because FCP is dominated by TTFB and render-blocking resources, it is chiefly useful as a way to attribute LCP problems: a slow FCP points at server or blocking-resource issues, while a fast FCP with a slow LCP points at the hero resource itself.
Example
FCP of 0.9 s alongside LCP of 4.0 s indicates the page paints quickly but the main image loads far too late.
Related terms
Time to First Byte
The interval between a navigation request starting and the first byte of the response arriving; a foundational input to LCP and a signal…
Render-blocking resources
Stylesheets and synchronous scripts in the head that must be downloaded and processed before the browser can paint anything.
Lighthouse
An open-source automated auditing tool in Chrome DevTools and PageSpeed Insights that runs lab tests for performance, accessibility, best…
Core Web Vitals
Google's set of three field-measured user experience metrics — LCP, INP and CLS — used as part of the page experience signals in ranking.