Web & SEO
What is largest Contentful Paint (LCP)?
Largest Contentful Paint (LCP) is the Core Web Vital that measures how long a page takes to render its largest visible element, marking the point a visitor perceives the page as loaded.
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Technical definition
LCP records the render time of the largest image, video poster, or block of text visible in the viewport, measured from when the page starts loading. Google's threshold for good is 2.5 seconds or less at the 75th percentile of real visits. Between 2.5 and 4 seconds needs improvement, and above 4 seconds is poor.
The element responsible is usually the hero image or the main headline. Common causes of a slow LCP are an oversized or unoptimized hero image, a slow server response, render-blocking CSS or JavaScript, and web fonts that delay text from painting.
In plain terms
How long until the main thing on the page shows up. Not the spinner, not the header, the actual content someone came for.
Under two and a half seconds is fine. Over four and people are leaving before they see anything.
Why it matters
LCP is the Core Web Vital small business sites fail most, and the cause is almost always one image. A hero photo exported straight from a camera at full resolution can be several megabytes, and on a phone connection that is the whole budget spent before anything else loads.
Three fixes cover most cases. Resize the hero image to the largest size it will actually display and serve it in a modern format. Do not lazy-load it, since delaying the one image that defines your score makes the score worse. And check the real number in Google Search Console rather than a lab test, because field data reflects the phones and connections your visitors actually have.
