LCP (Largest Contentful Paint) is one of Google’s Core Web Vitals metrics — and it’s arguably the most important one. It measures how long it takes for the largest piece of content on your page to load, which is essentially the metric for your page’s load time. If your LCP score is bad, it’s hurting your rankings AND driving visitors away.
In this guide, we break down exactly what LCP is, how to measure it properly, and the fixes that actually work. We also cover common “fixes” that are a complete waste of time — or can actually make things worse. Some of the steps are quite technical, so we’ve included a video version of this guide below.
Table of Contents
What Is Largest Contentful Paint (LCP)?
Simply put, LCP or Largest Contentful Paint, is the time at which the largest piece of content on your page has finished loading. This includes everything above the fold or “viewport” (the area visible to the user when the page first loads), whether that’s an image, video, or text block.
Think of it as the modern metric for load time — it’s the point where your visitor perceives the page as fully loaded. LCP is one of the three Core Web Vitals metrics from Google, and it’s the one that directly represents your page speed.
It’s important to understand that LCP is different from traditional page load time metrics. You can have a very high fully loaded time but still have a good LCP time. On today’s web, LCP is a better measure of site speed because it reflects the visitor’s perception of how fast the site loaded, rather than technical metrics like onload time or document complete time.
Google recognizes LCP as one of their Core Web Vitals metrics and it’s part of their ranking algorithm, which means LCP is important for both traffic and conversions.
What Should My LCP Time Be?
According to Google’s guidelines, here’s how LCP scores break down:
- Good: Under 2.5 seconds
- Needs Improvement: 2.5 to 4 seconds
- Poor: Over 4 seconds — you’re losing traffic
For your website to pass Core Web Vitals, over 75% of your real visitors need to experience an LCP time under 2.5 seconds. This is measured as a 28-day rolling average, so changes you make won’t show up in the data immediately. You’ll see warnings in Google Search Console if your pages fall into the “needs improvement” or poor zone.
Note That The Speed Of ALL Pages Matters
A common mistake when it comes to LCP timing is thinking that the homepage is the only page that needs improvement. While the homepage is probably the most popular page on your site, all pages matter to both Google and your users. Google’s Core Web Vitals has a metric called “Origin Summary” which is a collection of data across your entire site. Your homepage can load lightning fast but if all other pages are slow then you’re going to fail Core Web Vitals.
You Need Enough Traffic For Reliable Data
Core Web Vitals data requires approximately 50 to 100 visits per day to generate reliable metrics. If your site gets less than that, there may not be enough data to create a meaningful data set. Keep in mind that only Chrome-based browsers contribute to this data (including Microsoft Edge), so Safari and Firefox visits aren’t counted. This isn’t an exact threshold — it’s what we consistently see after optimizing thousands of sites.
Origin Data vs. Individual URL Data
There are two Core Web Vitals data sets to be aware of:
- Origin data: Site-wide data across your entire website
- Individual URL data: Data for a specific page — but only if that page gets enough traffic on its own
For most small business websites, only the homepage may have enough traffic for individual URL data. The rest of the site will rely on origin-level data. Don’t mix these two up when analyzing your scores. If you’re running a PageSpeed Insights test, you’ll see a toggle between “URL” and “Origin” data if the page has enough traffic for its own data set.
Load Speed Differs Per Device
The page load speed is going to differ depending on the device. A page that loads within 2.5 seconds on desktop might fail on mobile, and vice versa. Core Web Vitals data can be sliced by device type (mobile, desktop, all devices), so keep this in mind when analyzing your data.
Geography & Location Matters
Another important factor that impacts LCP is geographic location. If your site is hosted in the US and most of your visitors are also in the US, your visitors will get roughly the same LCP time. If your visitors are spread around the globe, they’ll get a varying experience depending on where they’re located and you may fail Core Web Vitals as a result. The best way to overcome this is to use a content delivery network (CDN), which we’ll cover in the fixes section below.
Field Data vs. Lab Data — Why This Matters
This is one of the most misunderstood aspects of web performance and most of what you read online misses this completely. There are two types of speed data:
Lab data comes from tests like PageSpeed Insights, Lighthouse, Pingdom, or GTmetrix. These run a simulated test that tries to approximate real-world speed — but it’s not what actual users experience.
Field data (also called Real User Measurement or RUM data) is collected from real Chrome-based browsers visiting your site. This is the data Google uses for Core Web Vitals and rankings. It’s probably the best measurement we have of how fast your website actually is.
Here’s the important part: PageSpeed Insights scores can be cheated. You’ll see companies guaranteeing a 100 score in PageSpeed Insights. What they’re often doing is pausing JavaScript and delaying content from loading until the user interacts with the site. The test only sees a fraction of your actual page, so the score looks great — but real users experience something different. You’ll probably still fail Core Web Vitals, and it may actually make the speed worse in the real world.
If you’re passing PageSpeed Insights but failing Core Web Vitals, this is likely what’s happening. Focus on field data, not lab scores.