Largest Contentful Paint

Largest Contentful Paint measures the time from navigation start to when the largest visible content element finishes rendering — usually the hero image, a video poster, or a big block of headline text. Anything slower than 2.5 seconds counts as a poor experience in Google’s scoring.

The best LCP wins come from removing whatever delays the largest element from painting. That’s usually a heavy hero image without proper width / height attributes, a font that blocks paint, or a JavaScript bundle that runs before the image is even decoded. Server-rendered HTML, an explicit `priority` attribute on the LCP image (Next.js terminology for `fetchpriority="high"`), and font subsetting cover most of the field.

LCP doesn’t have to be perfect to ship — but if your LCP is over 4 seconds and you’re serving e-commerce or content, you’re losing real money to bounce.