What is First Contentful Paint (FCP)?

First Contentful Paint (FCP) measures how long it takes for the very first piece of content - any text, image or visible element - to appear on screen. It is the moment the visitor knows something is happening:

• Good is under 1.8 seconds - that is Google’s published threshold for a fast first paint.
• It comes before LCP - FCP is the first thing to show; LCP is when the biggest thing has shown. A slow FCP makes everything after it feel slow.
• The usual cause is a slow server or render-blocking CSS - nothing can paint until the browser has the HTML and the styles it needs.

FCP is a diagnostic metric, not a Core Web Vital, but a poor one is an early warning that your server or stylesheets are holding the page up. Fix a slow FCP and your LCP almost always improves with it.