Metrics
Largest Contentful Paint (LCP)
Also: LCP
The render time of the largest content element visible in the viewport.
Definition
A Core Web Vital. Measures when the largest text block, image, or video in the initial viewport finishes rendering. Good < 2.5s, needs improvement 2.5-4.0s, poor > 4.0s. On JS-heavy sites, LCP is often a hero image or above-the-fold heading. Fonts, render-blocking JS, and hydration delays push LCP up.
See also
More in Metrics
Interaction to Next Paint (INP)
Worst-case latency between a user input and the next visual update.
Cumulative Layout Shift (CLS)
How much visible content unexpectedly shifts during a page lifetime.
Time to First Byte (TTFB)
The time between request and the first byte of response from the origin or CDN.
Time to Interactive (TTI)
The time until the main thread is reliably free to handle user input.
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