Glossary · Definition
LCP
LCP (Largest Contentful Paint) is the time from when a page starts loading to when the largest visible content element finishes rendering. Google's target is 2.5 seconds or less on the 75th percentile.
Definition
LCP (Largest Contentful Paint) is the time from when a page starts loading to when the largest visible content element finishes rendering. Google's target is 2.5 seconds or less on the 75th percentile.
What it means
LCP replaced older 'page load time' metrics because total load time isn't what users perceive — they care when the page looks loaded, which is usually when the biggest image, headline, or hero element has painted. LCP is measured in milliseconds and bucketed: ≤2.5s = Good, 2.5-4s = Needs Improvement, >4s = Poor. The usual LCP element is a hero image, a large heading, or a primary card. Identifying the LCP element for your page is the first step to optimization — tools like Chrome DevTools and Lighthouse will name it explicitly.
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Why it matters
LCP is the Core Web Vital that's most often in the Poor bucket for unoptimized sites. A site with a 6-second LCP is losing rankings AND losing users who bounce before the page finishes. Fortunately, it's also the most improvable — preload the LCP image, optimize image format (WebP), size, and compression, remove render-blocking resources, and most sites move from 4s+ to under 2.5s with a day of work.
Frequently asked questions
What counts as an LCP element?
Images, videos, background images, and block-level text nodes. The largest visible one during page load is the LCP element.
How do I improve LCP?
The biggest wins: optimize the LCP image (WebP format, correct size, preload), reduce render-blocking JS/CSS, eliminate layout thrashing before the LCP renders, and use a CDN for static assets.
Does LCP include JavaScript?
LCP is the first render of the largest element — if JS is blocking that render, yes, JS affects LCP. But the metric itself is purely visual.
Related terms
- DefinitionCore Web VitalsCore Web Vitals are three Google-defined metrics that measure the real-user experience of a web page: LCP (loading), INP (interactivity), and CLS (visual stability). They're a direct ranking signal as of 2021.
- DefinitionCLSCLS (Cumulative Layout Shift) measures how much visible content jumps around unexpectedly as a page loads. Google's target is 0.1 or less. It's the metric that scores how 'janky' a page feels.