# Why is CrUX data different from my RUM data?

DevFeed: [Why is CrUX data different from my RUM data?](<https://devfeed.tech/articles/why-is-crux-data-different-from-my-rum-data-4159.md>)

Original publisher: [Read original article](<https://web.dev/articles/crux-and-rum-differences?hl=en>)

Author: Barry Pollard X GitHub Mastodon Bluesky Homepage

Published: 2025-12-17T08:00:00Z

Content type: tutorial

Language: en

Sources: [web.dev: Articles](<https://devfeed.tech/sources/web-dev-articles.md>)

Topics: [real user monitoring](<https://devfeed.tech/topics/real-user-monitoring.md>)

Tags: [analytics](<https://devfeed.tech/tags/analytics.md>), [benchmarking](<https://devfeed.tech/tags/benchmarking.md>), [chrome](<https://devfeed.tech/tags/chrome.md>), [metrics](<https://devfeed.tech/tags/metrics.md>), [real-user-monitoring](<https://devfeed.tech/tags/real-user-monitoring.md>), [user-experience](<https://devfeed.tech/tags/user-experience.md>)

## AI overview

This guide explains why Core Web Vitals measurements from CrUX and real user monitoring can differ, and how RUM can provide finer-grained analysis to investigate site issues.

## Source excerpt

Learn about reasons why RUM data can show different Core Web Vitals numbers from CrUX.