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First Class Dev
PerformanceJuly 22, 2026· 5 min read

What is LCP (Largest Contentful Paint) and how to improve it

LCP measures the time until the largest visible element loads. Understand Google's 2.5 s threshold, what slows it down and how to fix it step by step.

LCP (Largest Contentful Paint) is the Core Web Vitals metric that measures how long the largest visible element — usually a hero image or the top block of text — takes to appear on screen. It is the main "has the site loaded yet?" signal in the visitor's perception.

What is a good LCP?

Google uses three ranges, measured at the 75th percentile of real visits (mostly on mobile):

  • Good: up to 2.5 seconds.
  • Needs improvement: between 2.5 and 4 seconds.
  • Poor: above 4 seconds.

The benchmark is mobile, not desktop: that is where most traffic lands and where network and CPU are slowest.

What usually slows LCP down

  • A heavy hero image, uncompressed or in an old format (JPEG/PNG instead of WebP/AVIF).
  • A slow server responding the first byte (high TTFB).
  • JavaScript and CSS that block rendering before content appears.
  • Fonts that hide text while the file downloads.

How to improve LCP

  • Serve the main image in WebP or AVIF, at the exact on-screen size, with width and height set.
  • Give the LCP element loading priority (preload / priority) and never lazy-load it.
  • Reduce TTFB with caching and hosting close to your audience.
  • Defer non-essential JavaScript and use font-display: swap so text shows immediately.

LCP is not technical vanity: according to Google, more than half of mobile visits are abandoned when a page takes longer than 3 seconds to load. Every second shaved off LCP usually translates directly into more people who stay and convert.

How to measure your site's LCP

You can measure your site's LCP for free, in seconds, with First Class Dev's Speed X-Ray — it runs Google's official measurement (PageSpeed Insights) and shows what is blocking it and what to fix first.

Measure your site now, for free.

The Speed X-Ray runs Google's official measurement and shows what to fix first.

Run the free Speed X-Ray
Frequently asked questions
What is the ideal LCP value?

Up to 2.5 seconds at the 75th percentile of visits, measured on mobile. Between 2.5 and 4 seconds the metric needs improvement; above 4 seconds Google considers it poor.

What is usually the LCP element?

Almost always the largest image above the fold or the largest top block of text — such as the hero image, a banner or the main heading. It is the item that dominates the first screen.

Does LCP affect Google ranking?

Yes. LCP is one of the three Core Web Vitals Google uses as a page experience signal. On its own it won't guarantee first place, but a poor LCP hurts sites competing for the same keywords.

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