This translation has not been editorially reviewed yet. The German version is authoritative. Deutsche Fassung →
Checking FCP: when the first pixel of content appears
First Contentful Paint measures when any content first becomes visible at all — text, an image, or graphics. Together with the server response time, it separates two quite different causes: the server takes a long time, or the browser isn't getting around to drawing.
- If FCP sits close above TTFB, the browser is working briskly and the bottleneck is the server. If there's a big gap, something is blocking rendering — usually stylesheets or scripts loaded in the page head.
- A common case is an embedded font that holds up text rendering. The browser has the text, but it's waiting on the file.
FAQ
What's the difference between FCP and LCP?
FCP measures the first visible content, LCP the largest. A page can show something very quickly and still take a long time before the essential part is in place.
Which of the two values matters more?
LCP, because it comes closer to the impression of usability. FCP is mainly valuable for troubleshooting.