Core Web Vitals

Core Web Vitals are three measurements Google uses to describe how a page feels to use: how fast the main content appears, how quickly the page responds to input, and how much the layout moves while loading. They are a ranking signal, and a small one.

The three measurements

  • LCP, largest contentful paint. How long until the biggest thing on screen has loaded. Good is under 2.5 seconds.
  • INP, interaction to next paint. How long the page takes to visibly respond when someone taps or clicks. Good is under 200 milliseconds.
  • CLS, cumulative layout shift. How much content jumps around while loading. Good is under 0.1.

An honest note on how much they matter

Core Web Vitals are a ranking signal, but a weak one compared with whether the page answers the question. A fast page about nothing will not outrank a slow page that is genuinely useful.

They are still worth fixing, for a less roundabout reason: a page that loads slowly and jumps around loses people before they read it. That costs you directly, whatever the ranking effect is.

The usual culprits

Oversized images, images without dimensions set, fonts that block rendering, and third-party scripts. In that order, most of the time.

Related terms

Crawling

Crawling is how search engines read your website: a program visits each page, follows the links, and records what it finds. If a page cannot be crawled, it cannot rank. Digger crawls your site the same way, which is how problems are found before they cost you visitors.

Indexing

Indexing is a search engine deciding to keep a page it has crawled, and storing it so it can be returned for a search. A page can be crawled and still not indexed, usually because the engine judged it thin, duplicated, or not worth storing.