Largest Contentful Paint (LCP) measures how long it takes for the biggest piece of content on the screen, usually a hero image, a video or a large block of text, to appear after someone starts loading a page. It's one of Google's three Core Web Vitals, along with Interaction to Next Paint and Cumulative Layout Shift.
For businesses, LCP is the closest single number to "how fast does this page feel?" A slow LCP means visitors stare at a blank or half-loaded screen, and some leave before they ever see your offer. It's also one of the Core Web Vitals that Google says its ranking systems use.
What is Largest Contentful Paint?
web.dev's LCP guide says the metric "reports the render time of the largest image, text block, or video visible in the viewport," measured from when the user first navigated to the page.
The elements that count include images (including images inside an SVG), videos, elements with a CSS background image loaded from a URL, and block-level elements that contain text. The browser updates its LCP candidate as larger elements render, and it stops reporting new candidates as soon as the user interacts with the page, such as by tapping, scrolling or pressing a key.
The thresholds are:
- Good: 2.5 seconds or less
- Needs improvement: more than 2.5 seconds, up to 4 seconds
- Poor: more than 4 seconds
Google recommends measuring at the 75th percentile of page loads, split by mobile and desktop. In other words, a page passes when at least 75% of real visits hit 2.5 seconds or better.
Why LCP matters
It's part of how Google assesses page experience. Google's page experience documentation says "Core Web Vitals are used by our ranking systems." It's also clear that there's no single page experience signal and that good scores alone don't guarantee top placement.
It reflects real visitors. Search Console's Core Web Vitals report uses field data from the Chrome UX Report, collected from real Chrome users over the last 28 days. That makes LCP a practical health check on how your pages load for actual customers on actual devices.
Slow loading costs attention. Every extra second of waiting is a chance for a visitor to give up. That matters for anyone arriving from search, ads or AI answers who wants to confirm a detail quickly.
How LCP works
The four parts of LCP
web.dev's guide to optimizing LCP breaks the metric into four subparts:
- Time to First Byte (TTFB): how long the server takes to start sending the HTML.
- Resource load delay: the gap between TTFB and when the browser starts downloading the LCP resource, such as the hero image.
- Resource load duration: how long that resource takes to download.
- Element render delay: the time between the download finishing and the element actually appearing.
As a rough guide, web.dev suggests most of the time should go to TTFB and resource load duration, about 40% each, with load delay and render delay each under 10%. It stresses that these are guidelines, not strict rules.
Field data vs. lab data
Field data comes from real users, through the Chrome UX Report, Search Console and PageSpeed Insights. Lab data comes from simulated tests in tools like Lighthouse. Google's Core Web Vitals assessment is based on field data, while lab tools help you diagnose the cause.
A recent change for single-page apps
In October 2026, Chrome added experimental soft-navigation versions of the Core Web Vitals, including LCP, to the Chrome UX Report. They measure in-app page changes on single-page applications. Google says stable Core Web Vitals scores are unchanged while the experimental versions are evaluated, and Search Console will switch to the new data only once they graduate, which the team is aiming for in May 2027.
How to improve LCP
- Find your LCP element. PageSpeed Insights and Chrome DevTools show which element is being measured on each template.
- Don't lazy-load it. web.dev says never to lazy-load your LCP image. Our lazy loading entry explains why.
- Prioritize it. Add fetchpriority="high" to the likely LCP image. web.dev warns that setting high priority on more than one or two images makes it unhelpful.
- Make it discoverable early. If the image is only referenced in CSS or JavaScript, preload it so the browser can start downloading sooner.
- Shrink the file. Use modern image formats, sensible dimensions and compression.
- Speed up the server. Caching, a CDN and lighter server work all reduce TTFB.
- Put content in the HTML. Pages that build their main content with client-side JavaScript can have long render delays. Server-side rendering or static rendering helps.
Common mistakes and misconceptions
"My Lighthouse score is what Google uses." Lighthouse is lab data. Google's Core Web Vitals assessment is based on field data from real Chrome users.
"LCP is the same as page load time." LCP measures when the main content appears, not when everything finishes loading. A page can have a good LCP while other scripts are still loading in the background.
"A good desktop score means we're fine." Mobile and desktop are measured separately, and mobile is often slower. With mobile-first indexing, Google mainly uses the mobile version of your pages, so check both.
"Fixing LCP will boost rankings." It improves the experience and can help, but Google says good Core Web Vitals scores alone don't guarantee top placement.
LCP vs. First Contentful Paint
First Contentful Paint (FCP) marks when anything first appears, even a logo or a background. LCP marks when the largest, most meaningful element appears. FCP tells you the page has started; LCP tells you the main content has arrived. Only LCP is a Core Web Vital.
How Butter approaches LCP
At Butter, we look at Core Web Vitals as part of technical health, alongside crawlability and indexing, rather than as a standalone vanity score. We start with field data from Search Console, because that is what reflects your real visitors, then use lab tools to find the cause.
On our GEO+SEO plan, technical SEO fixes and unlimited on-page optimization give us room to address issues like oversized hero images and heavy scripts on key templates. The Butter Analytics dashboard connects to Google Search Console and Google Analytics, so you can see whether changes hold up over time. On the GEO plan, we include performance issues in our monthly on-page recommendations. A better LCP improves the experience for every visitor and can help in search, but we never promise rankings from speed work alone. Our SEO services page has the details.
Frequently asked questions
What is a good LCP score?
Google considers an LCP of 2.5 seconds or less good, more than 2.5 and up to 4 seconds needs improvement, and more than 4 seconds poor. Aim to hit the good threshold for at least 75% of page loads on both mobile and desktop.
What usually causes a slow LCP?
Common causes include a slow server response, a large or late-discovered hero image, lazy loading applied to the main image, render-blocking CSS or JavaScript, and main content that only appears after client-side JavaScript runs.
Is LCP a Google ranking factor?
Google says Core Web Vitals, including LCP, are used by its ranking systems. But there is no single page experience signal, and good scores alone don't guarantee top rankings. Treat it as one factor among many.
Where can I check my site's LCP?
Google Search Console's Core Web Vitals report shows field data grouped by similar pages. PageSpeed Insights shows field and lab data for individual URLs, and Chrome DevTools can identify which element is the LCP.