What are Core Web Vitals? A plain-English guide
Google’s Core Web Vitals explained without jargon: what LCP, INP and CLS measure, the ‘good’ thresholds and how to improve them.
The three measurements
Largest Contentful Paint (LCP) measures how long the main content takes to appear. Good is 2.5 seconds or less.
Interaction to Next Paint (INP) measures how quickly the page responds when someone taps or clicks. Good is 200 milliseconds or less. INP replaced First Input Delay in March 2024.
Cumulative Layout Shift (CLS) measures how much the page jumps around as it loads. Good is 0.1 or less.
Where the data comes from
Google uses data from real Chrome users, called field data. You can see it in Search Console under Core Web Vitals and in PageSpeed Insights.
Common causes and fixes
- Slow LCP: large hero images, slow hosting, render-blocking scripts
- Poor INP: heavy JavaScript, too many third-party tags
- High CLS: images without set dimensions, late-loading banners and fonts
Do they really matter?
They’re one signal among many, and great content still wins. But when two pages are close, a better experience helps, and faster pages convert more visitors regardless of rankings.
Frequently asked questions
What are good Core Web Vitals scores?
LCP of 2.5 seconds or less, INP of 200 milliseconds or less and CLS of 0.1 or less, measured at the 75th percentile of visits.
Where can I check my Core Web Vitals?
In Google Search Console and PageSpeed Insights.
What replaced First Input Delay?
Interaction to Next Paint (INP) became a Core Web Vital in March 2024.
