What is LCP by FCP
LCP by FCP shows the Largest Contentful Paint (LCP) values in relation to First Contentful Paint (FCP) - the moment the first visible element appears on the screen. This lens helps you understand whether a fast start also leads to a fast meaningful load, or whether things slow down after the initial paint.
Healthy LCP by FCP sample
Should you worry
A healthy LCP by FCP lens reveals consistency - if the first visible content appears quickly and the largest content follows shortly after, you're doing it right. Good FCP paired with good LCP is the ideal outcome: a fast visual start and fast visual completion.
Even if FCP isn’t instant, it's still okay - as long as the LCP isn’t far behind. Pages with a moderate FCP can still feel fast when the LCP follows closely and the layout is stable.
Unhealthy LCP by FCP sample
You may notice mismatches like:
Good FCP, poor LCP: A quick first impression followed by long delays before the page feels complete. Often caused by lazy-loading critical content, render-blocking scripts, or waiting for images that aren’t prioritized.
Poor FCP and poor LCP: Nothing shows quickly and it takes too long for meaningful content to appear. This usually indicates bottlenecks both in rendering start and content load.
Good FCP, Needs improvement LCP: Could feel like a fast page that just “hangs” before showing the main content - frustrating for users who think the page is ready.
This lens helps reveal deceptive “fast starts” where users are misled by early visual signals but end up waiting longer than expected.
Resolving unhealthy LCP by FCP
Go-to action plan to resolve an unhealthy LCP by FCP:
Ask Uxi to analyze your LCP by FCP values and suggest improvements.
Use Filters to isolate sessions where FCP is good but LCP is poor, then check what’s loading after the FCP - images, fonts, or third-party elements are common culprits.
Simulate LCP of the suspected lens to see if fixing it will resolve the slow LCP by FCP. If yes, this is where the resolution focus should be.
Use an automated LCP optimization tool like Navigation AI to improve your LCP by FCP values.
Once you’ve improved LCP, set an alert to be the first to know if it starts worsening again.
Try it yourself
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