Our AI writing assistant, WriteUp, can assist you in easily writing any text. Click here to experience its capabilities.

Largest Contentful Paint (LCP)

Summary

This article discusses the Largest Contentful Paint (LCP) metric, which measures how quickly the main content of a web page loads and is visible to users. It explains which elements are considered, how the size of the element is determined, and how the metric differs from the First Contentful Paint (FCP) metric. It also provides examples of how LCP is reported, how to measure LCP in the lab and in the field, and how to improve LCP.

Q&As

What is Largest Contentful Paint (LCP)?
Largest Contentful Paint (LCP) is a metric that reports the render time of the largest image or text block visible within the viewport, relative to when the page first started loading.

What elements are considered for LCP?
The types of elements considered for LCP are elements, elements inside an element,

How is an element's size determined for LCP?
The size of the element reported for Largest Contentful Paint is typically the size that's visible to the user within the viewport. If the element extends outside of the viewport, or if any of the element is clipped or has non-visible overflow, those portions do not count toward the element's size. For image elements that have been resized from their intrinsic size, the size that gets reported is either the visible size or the intrinsic size, whichever is smaller. For text elements, only the size of their text nodes is considered (the smallest rectangle that encompasses all text nodes). For all elements, any margin, padding, or border applied via CSS is not considered.

How is LCP different from First Contentful Paint (FCP)?
LCP measures when the main content is painted, so it is intended to be more selective than FCP which measures when any content is painted to screen.

How can LCP be measured?
LCP can be measured in the lab or in the field, and it's available in Chrome User Experience Report, PageSpeed Insights, Search Console (Core Web Vitals report), web-vitals JavaScript library, Chrome DevTools, Lighthouse, and WebPageTest.

AI Comments

👍 This article provides an in-depth and comprehensive overview of the largest contentful paint (LCP) metric, its importance, and how to measure it.

👎 This article is overly long and could be shortened to make the information more concise and easier to comprehend.

AI Discussion

Me: It's about Largest Contentful Paint (LCP). It explains how to measure the time it takes for the main content of a web page to load, and what a good LCP score is. It also explains how elements are determined to be the largest contentful element, and how to measure LCP in the lab and in the field.

Friend: That's interesting. It seems like this metric could be very useful for web developers. What are some of the implications of this article?

Me: One of the implications is that web developers now have a better way to measure how quickly the main content of a web page loads and is visible to users. This will allow developers to create faster loading times and better user experiences. Another implication is that web developers can use the Largest Contentful Paint API to measure LCP in JavaScript, making it easier to track and analyze. Finally, the article mentions that sometimes the most important content on a page may not be the largest element, so developers may need to use the Element Timing API to measure the render times of other elements.

Action items

Technical terms

Largest Contentful Paint (LCP)
A metric that reports the render time of the largest image or text block visible within the viewport, relative to when the page first started loading.
First Contentful Paint (FCP)
A user-centric performance metric that captures the very beginning of the loading experience.
First Meaningful Paint (FMP)
A performance metric that captures more of the loading experience after the initial paint.
Speed Index (SI)
A performance metric that helps capture more of the loading experience after the initial paint.
Containing Block
A CSS term that refers to the element that contains a given element.
Timing-Allow-Origin Header
A security header that allows a web server to specify which origins are allowed to read timing information.
Font Block Period
The period of time between when a web font is requested and when it is available for use.
Web-Vitals JavaScript Library
A library that can be used to measure LCP in JavaScript.

Similar articles

0.8300145 When CSS Blocks

0.8047026 June 2023 Google SEO office hours

0.7933719 Design Decisions for Scaling Your High Traffic Feeds

0.7933589 Design Decisions for Scaling Your High Traffic Feeds

0.7894954 Understanding React Server Components self.__wrap_n=self.__wrap_n||(self.CSS&&CSS.supports("text-wrap","balance")?1:2);self.__wrap_b=(t,n,e)=>{e=e||document.querySelector(`[data-br="${t}"]`);let s=e.parentElement,r=O=>e.style.maxWidth=O+"px";e.style.maxWidth="";let o=s.clientWidth,u=s.clientHeight,a=o/2-.25,l=o+.5,d;if(o){for(r(a),a=Math.max(e.scrollWidth,a);a+1{self.__wrap_b(0,+e.dataset.brr,e)})).observe(s):process.env.NODE_ENV==="development"&&console.warn("The browser you are using does not support the ResizeObserver API. Please consider add polyfill for this API to avoid potential layout shifts or upgrade your browser. Read more: https://github.com/shuding/react-wrap-balancer#browser-support-information"))};self.__wrap_n!=1&&self.__wrap_b(":R1kb3sla6:",1)

🗳️ Do you like the summary? Please join our survey and vote on new features!