LCP (Largest Contentful Paint)
How long until the main thing on the page appears.
What it is
Largest Contentful Paint measures the moment the biggest visible element — usually a hero or product image — finishes rendering. It is one of Google's three Core Web Vitals and the one shoppers feel as "the page is slow".
Why it costs you money
On a product page the LCP element is nearly always the main image, and every second before it appears is a second the shopper spends looking at an empty box. Google's published threshold treats 2.5 seconds or less as good, measured on real visitors rather than a lab run.
How to check it yourself
Open your Core Web Vitals report in Search Console, or run a URL through our speed check. If the number is poor, look first at the size and format of the main image and at whether something lazy-loaded it when it should have loaded eagerly.