What are Core Web Vitals? The three speed metrics Google measures
Definition
Core Web Vitals are three measurements Google uses to describe how a page feels to a real visitor: Largest Contentful Paint for loading, Interaction to Next Paint for responsiveness and Cumulative Layout Shift for visual stability. A page passes when 75% of real visits score "good" on all three.
Why store owners should care
Shoppers judge speed by feel, and these three metrics turn that feeling into numbers. Google reports them for sites with enough real traffic and uses them as one signal among many in search. More practically, a store that loads slowly, reacts late or jumps around loses shoppers before the product has a chance.
The three metrics and their thresholds
Largest Contentful Paint (LCP) is good at 2.5 seconds or less and poor above 4 seconds.
Interaction to Next Paint (INP) is good at 200 milliseconds or less and poor above 500 milliseconds.
Cumulative Layout Shift (CLS) is good at 0.1 or less and poor above 0.25.
Where the numbers come from
Google collects them from Chrome users who opt in, in a dataset called the Chrome UX Report. A page needs enough visits over 28 days to appear in it. Tools such as PageSpeed Insights show this field data beside a lab test run on a simulated phone.
A common mistake
Chasing a perfect lab score. A store can pass Core Web Vitals in the field with a lab score in the 60s, and a 100 in the lab does not guarantee real visitors have a fast experience.
Frequently asked questions
Are Core Web Vitals a ranking factor?
Google has said they are part of its page experience signals. They are one input among many, and content relevance matters far more.
How do I see mine?
Run your store address through PageSpeed Insights, or open the Core Web Vitals report in Google Search Console.