# Core Web Vitals

> Google's three field metrics for loading, responsiveness and visual stability, measured on real visits rather than in a lab.

Largest Contentful Paint asks when the main thing appeared. Interaction to Next Paint asks how long the page took to respond when someone tried to use it. Cumulative Layout Shift asks how much the content moved under them while it loaded. Together they approximate the experience of a page well enough to be worth optimising directly.

The distinction that matters is field versus lab. A lab tool scores one run on one machine on a fast connection; the field data is what actual visitors experienced on the phones and networks they actually have, at the 75th percentile, and the two regularly disagree. A perfect lab score alongside failing field data usually means the audience is on worse hardware than the person running the test.

## Related terms

- https://dfieldsolutions.com/en/glossary/lcp.md
- https://dfieldsolutions.com/en/glossary/hydration.md
- https://dfieldsolutions.com/en/glossary/static-generation.md

---

Source: https://dfieldsolutions.com/en/glossary/core-web-vitals
DField Solutions — Dunakeszi, Hungary — dezso@dfieldsolutions.com
Booking: see https://dfieldsolutions.com/en/contact