---
title: "Core Web Vitals"
description: "Google's set of real-world user experience metrics — Largest Contentful Paint (LCP), Interaction to Next Paint (INP), and Cumulative Layout Shift (CLS) — used as ranking signals in the Page Experience update."
url: "https://skribra.com/glossary/core-web-vitals"
type: "glossary-term"
category: "Technical SEO"
updated: "2026-06-08"
---

# Core Web Vitals

**Definition.** Google's set of real-world user experience metrics — Largest Contentful Paint (LCP), Interaction to Next Paint (INP), and Cumulative Layout Shift (CLS) — used as ranking signals in the Page Experience update.

**In short.** Core Web Vitals measure how fast and stable your pages feel to real users. Google uses these as ranking signals, so improving them helps both user experience and SEO simultaneously.

## Key points

- LCP measures loading performance — the time it takes for the largest visible content element to render (target: under 2.5 seconds)
- INP measures interactivity — how quickly the page responds to user input like clicks or taps (target: under 200ms). INP replaced FID as a Core Web Vital in March 2024
- CLS measures visual stability — how much the page layout shifts unexpectedly during loading (target: score under 0.1)
- Google measures Core Web Vitals using real Chrome user data from the CrUX (Chrome User Experience Report) dataset

## Why Core Web Vitals Are a Ranking Factor

Google officially incorporated Core Web Vitals into its ranking algorithm in June 2021 as part of the Page Experience update[1]. The rationale: fast, stable, responsive pages deliver better user experiences, and Google's mission is to surface the best results for users. In competitive niches where content quality is comparable, page experience can be a tiebreaker. Google measures these metrics using field data (real user measurements) from the Chrome User Experience Report — so real-world performance across different devices and network conditions matters, not just lab tests[2].

## How to Measure Your Core Web Vitals

Google Search Console's Core Web Vitals report shows LCP, INP, and CLS data segmented by mobile and desktop, categorized as Good, Needs Improvement, or Poor[2]. PageSpeed Insights provides both lab (simulated) and field (real user) data for any URL. The most common LCP culprits are unoptimized hero images and slow server response times. CLS issues usually stem from images without explicit dimensions, late-loading ads, or injected content. INP problems often relate to JavaScript blocking the main thread[1]. These metrics also intersect with your [Indexing](https://skribra.com/glossary/indexing) health — Google uses page experience as a tiebreaker after relevance and [authority signals](https://skribra.com/glossary/e-e-a-t).

## Practical Improvements for Each Metric

To improve LCP: compress and serve images in next-gen formats (WebP, AVIF), use a CDN to reduce server response time, preload the LCP element, and eliminate render-blocking resources[1]. For CLS: always define width and height attributes on images and videos, use CSS aspect-ratio for responsive media, avoid inserting content above existing content after load. For INP: minimize JavaScript execution time, defer non-critical scripts, and break up long tasks. These improvements benefit all visitors regardless of search engine — which reinforces [trustworthiness](https://skribra.com/glossary/e-e-a-t) and keeps [Bounce Rate](https://skribra.com/glossary/bounce-rate) low.

## Related terms

- [Crawlability](https://skribra.com/glossary/crawlability): The ability of search engine bots to access, navigate, and read the pages on your website without encountering technical barriers.
- [Indexing](https://skribra.com/glossary/indexing): The process by which a search engine stores and organizes crawled web pages in its database so they can be retrieved and displayed in search results.
- [Organic Traffic](https://skribra.com/glossary/organic-traffic): Website visitors who arrive through unpaid search engine results, as opposed to paid ads, social media, direct visits, or referral links.
- [Bounce Rate](https://skribra.com/glossary/bounce-rate): The percentage of sessions in which a user visits only one page on your website and leaves without interacting further, as measured by Google Analytics.

## Sources

1. [web.dev — Web Vitals Overview](https://web.dev/articles/vitals)
2. [Google Search Central — Core Web Vitals and Google Search](https://developers.google.com/search/docs/appearance/core-web-vitals)

## Machine-readable index

- HTML version of this page: https://skribra.com/glossary/core-web-vitals
- Site index for agents: https://skribra.com/llms.txt
- Sitemap: https://skribra.com/sitemap.xml
- Public REST API: https://skribra.com/api/v1
- OpenAPI specification: https://skribra.com/openapi.json