Page speed metrics for Core Web Vitals and performance
Marfeel captures a comprehensive set of page speed metrics so you can accurately assess your site’s performance. Three of these metrics, LCP, INP, and CLS, determine your website’s Core Web Vitals. These metrics directly affect user experience and how Google evaluates and ranks your site, so monitoring them carefully and taking steps to improve them is essential.
Marfeel uses Real User Monitoring (RUM) to gather this data. Some of it is sourced from Mozilla’s Performance API. You can also filter and identify CWV offenders to pinpoint which pages need attention.
Metrics
Section titled “Metrics”LCP, Largest Contentful Paint
Section titled “LCP, Largest Contentful Paint”LCP measures the time it takes for a page’s largest image or text block to render relative to when the page first loads. A good LCP score is under 2.5 seconds. Visit our documentation to learn more about LCP.
CLS, Cumulative Layout Shift
Section titled “CLS, Cumulative Layout Shift”CLS measures the amount by which a visible element within the viewport changes its position unexpectedly. For example, a user may be about to click a button when an ad loads above it, shifting the button down and causing the user to click the ad instead. A good CLS score is less than 0.1. Visit our documentation to learn more about CLS.
FID, First Input Delay
Section titled “FID, First Input Delay”FID measures the time between when a user attempts to interact with a page and when the browser starts processing event handlers in response. A good FID score is under 100 ms. Visit our documentation to learn more about FID.
INP, Interaction to Next Paint
Section titled “INP, Interaction to Next Paint”INP measures the time from when a user clicks or types on a page until the page next updates visually. It captures the slowest interaction on the page. A good INP score is less than 200 ms. Visit our documentation to learn more about INP.
TBT, Total Blocking Time
Section titled “TBT, Total Blocking Time”TBT measures the total time after First Contentful Paint (FCP) during which the main thread was blocked long enough to prevent input responsiveness. A good TBT score is less than 200 ms. Visit our documentation to learn more about TBT.
TTFB, Time to First Byte
Section titled “TTFB, Time to First Byte”TTFB measures the time between the request for a resource and when the first byte of a response begins to arrive. A good TTFB score is under 800 ms. Visit our documentation to learn more about TTFB.
DOM Content Loaded Time
Section titled “DOM Content Loaded Time”DOM Content Loaded Time measures when all nodes in the page have been constructed in the DOM tree, without waiting for images and CSS to finish loading. Visit our documentation to learn more about DOM Content Loaded.
Onload event
Section titled “Onload event”The onload event is a DOM lifecycle event that fires when an object has fully loaded. It is most commonly used within the body element to execute a script once a web page has completely loaded all content, including images and iframes. Visit our documentation to learn more about Onload event.
Page views with Web Vitals
Section titled “Page views with Web Vitals”This metric represents the total number of page views where Web Vitals data was successfully collected. It helps you understand how much of your traffic is eligible for Core Web Vitals reporting and serves as a key baseline for evaluating how representative your performance metrics are.
To view a comprehensive list of all of Marfeel’s Metrics and Dimensions, visit our Glossary.
Which page speed metrics determine Core Web Vitals?
LCP (Largest Contentful Paint), INP (Interaction to Next Paint), and CLS (Cumulative Layout Shift) are the three metrics that determine your website’s Core Web Vitals score.
How does Marfeel collect page speed data?
Marfeel uses Real User Monitoring (RUM) to gather page speed data from actual visitors. Some metrics are sourced from Mozilla’s Performance API.
What is a good LCP score?
A good LCP score is under 2.5 seconds. LCP measures the time it takes for a page’s largest image or text block to render relative to when the page first loads.