Largest Contentful Paint (LCP) measures when the largest eligible image or text block becomes visible. Interaction to Next Paint (INP) assesses responsiveness to interactions such as clicks, taps and key presses. Cumulative Layout Shift (CLS) measures unexpected movement in the layout.
INP replaced First Input Delay (FID) in March 2024. Older guides that still describe FID as a current Core Web Vital need updating. These are three separate measurements, not a single overall score for the quality of your website.
Google’s Core Web Vitals guidance defines good thresholds as LCP of 2.5 seconds or less, INP of 200 milliseconds or less and CLS of 0.1 or less. Assessment uses the 75th percentile of recorded page visits, considered separately for mobile and desktop.
A fast test on a developer’s laptop does not establish that most customers have a good experience. Look at the devices, connections and page types your audience uses, and treat the thresholds as a useful baseline rather than the only objective for the project.
A slow server response, large image or delayed resource can make visitors wait for the content they came to see. Identify the actual LCP element on the affected template before choosing a fix. It might be a prominent photograph, a product image or a heading, rather than the element you expected.
Check image dimensions and compression, delivery and caching, and resources that block rendering. Avoid lazy-loading the main image when it needs to appear immediately. Google’s LCP documentation explains the metric and provides a starting point for diagnosis.
A page can appear quickly yet feel slow when somebody opens the menu or chooses a product option. INP helps identify that gap. Test important interactions across the visit, including filters, forms, tabs and basket actions, rather than stopping once the initial page has loaded.
Heavy JavaScript, lengthy tasks and expensive rendering can delay feedback. Investigate the interaction that is slow, reduce unnecessary work and check third-party tools. The INP guide explains how responsiveness is assessed. Improvements should make the interface feel prompt while preserving the behaviour users need.
Unexpected movement can push a button away just as someone tries to use it. Reserve space for images, video and embedded content, and check what happens when fonts, banners and third-party widgets load. Review the page after loading as well as during the first few seconds.
Google’s CLS documentation describes how layout shifts are measured. For a business website, the practical aim is a stable journey in which people can read, navigate and complete actions without the interface moving unexpectedly around them.
PageSpeed Insights can show real-user data from the Chrome User Experience Report alongside a laboratory test. These answer different questions. Field data reflects recorded visits over time; a laboratory run helps reproduce issues under particular test conditions. A Lighthouse score is not the same as passing Core Web Vitals.
Search Console groups URLs with similar experiences, which can help you identify affected templates. Where there is not enough field data, the absence of a result does not mean the page has passed or failed. Test representative pages and record what you changed so that you can compare the evidence afterwards.
Start with important landing pages and the journeys that lead to enquiries or sales. Fix a shared template problem before repeating isolated changes across individual URLs. Check the result on mobile and desktop, and allow time for field reporting to reflect the improved experience.
Good Core Web Vitals support usability and are used by Google’s ranking systems, but they do not guarantee rankings or replace useful content. Webheads can help investigate performance as part of a technical SEO review, with priorities tied to your website and business goals.
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