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What are Core Web Vitals?

Core Web Vitals are three measurements of how a web page feels to real visitors: how fast the main content loads, how quickly the page responds to a tap, and how much it jumps around while loading.1

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Why it matters for a small business

The three are Largest Contentful Paint (LCP), Interaction to Next Paint (INP) and Cumulative Layout Shift (CLS). A good page has LCP within 2.5 seconds, INP of 200 milliseconds or less, and CLS of 0.1 or less.1

Each target should hold for at least three in four page loads, measured separately on phones and on computers.1

Google recommends good Core Web Vitals for success in Search, and says they line up with what its ranking systems try to reward.2

A made-up villa in Kotor

Mila's home page opened with a full-screen slideshow, and an availability calendar pushed the text down as it loaded. PageSpeed Insights flagged a slow LCP and a high CLS on phones. She swapped the slideshow for one photo and gave the calendar a fixed height.

How to check it yourself

  1. Test your home page in PageSpeed Insights

    Enter the address. It reports phones and computers separately, so read the phone results first.3

  2. Trust real visits over one test run

    The field data at the top comes from real Chrome users; the lab score below is a single run. web.dev says only field data shows the full picture.1

  3. Open the report in Search Console

    Its Core Web Vitals report groups your pages by how they perform for real visitors.2

  4. Start with the biggest image

    LCP times the largest image or text block on screen, so a large photo at the top of the page is often what decides it.4

Questions about Core Web Vitals

Do Core Web Vitals matter for AI search?

Google's AI search guide lists a good page experience, on every device and with little delay, among the technical basics.5

Why does my score change between tests?

A lab test depends on the device and network of that one run. web.dev says real performance varies with each visitor's device, connection and what else is running.1

Where this comes from

  1. Core Web Vitals are LCP (loading, good within 2.5 seconds), INP (interactivity, good at 200 milliseconds or less) and CLS (visual stability, good at 0.1 or less), measured at the 75th percentile of page loads on mobile and desktop; field data from real users powers PageSpeed Insights and Search Console, and only field data captures the full pictureweb.dev
  2. Google recommends good Core Web Vitals for success with Search, in line with what its core ranking systems reward; Search Console's Core Web Vitals report shows how pages perform (last updated 10 December 2025)developers.google.com
  3. PageSpeed Insights, Google's free test of a page's speed on phones and computerspagespeed.web.dev
  4. LCP reports the render time of the largest image, text block or video visible in the viewportweb.dev
  5. Google's guide to generative AI search: AEO and GEO describe work on visibility in AI search, which Google treats as SEO; its AI features retrieve pages from the Search index and link those that support the answer; Google Search ignores llms.txt files; no special schema.org markup is needed; Business Profiles help local businesses show in AI responses; measure with the Generative AI performance report; no third-party tool sees Google's ranking or AI systems (last updated 10 July 2026)developers.google.com

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