Core Web Vitals

Each metric times something a visitor notices. LCP is how long the largest image or block of text in the first view takes to appear. INP watches the clicks, taps and key presses during a visit and reports one of the slowest, measured until the screen changes in reply. CLS adds up how far things jump while the page is open. INP replaced First Input Delay, which timed only the first interaction, on 12 March 2024.

Google judges a page at the 75th percentile of real visits, with phones and desktops counted apart, so three visits in four have to meet the threshold. Good is an LCP of 2.5 seconds or less, an INP of 200 milliseconds or less and a CLS of 0.1 or less. The figures come from real Chrome visits, so a new site with little traffic may have none yet.

Google says good Core Web Vitals align with what its core ranking systems reward. The larger cost is on the page itself. A heading that appears after five seconds on a phone, or a form that jumps as an image loads above it, loses some of the people who came. The thresholds are a floor for the pages buyers land on, and they should be checked on a phone.

We measured our own site in November 2026. Lab runs on the live site, simulating a slow phone, put the largest element at 6.3 seconds on the home page and 5.6 to 6.1 on a service page, against 1.1 on a case study. In each slow case it was hero text, in the HTML from the first paint and held back by the entrance animation.

On 14 November the entrance moved to a CSS clock that starts at first paint. On a throttled phone the first text went from about 4.6 seconds to between 2.4 and 2.7, and it now shows with JavaScript off. Lighthouse’s default figure did not move, because it times a fast load in which the entrance still plays. We have no figures from real visits yet.

Say a landing page’s hero image weighs 1.8 MB and starts loading only after the stylesheet and two scripts. Field data puts its LCP at 4.3 seconds on phones, which is poor. Serving the image at the size it is shown, in a modern format, and telling the browser to fetch it first brings LCP to 2.3 seconds. A cookie banner that pushes the page down as it arrives still adds 0.15 of layout shift, until it is given a reserved space.