Above the Fold
Above the fold is everything a visitor sees before scrolling. On the web it varies by device, so it is a zone rather than a fixed line. What sits there decides whether most visitors keep reading or leave within a few seconds.
Why it matters for your rankings
The first screen carries a disproportionate share of the work. Visitors decide within seconds whether a page is relevant, and most of that judgement happens without a single scroll. If the top of your page is occupied by a stock image and a vague slogan, you spend your best real estate saying nothing.
It also affects Core Web Vitals directly. Largest Contentful Paint almost always measures an element above the fold, so a heavy hero image delays the metric Google actually records. Cumulative Layout Shift is usually caused by banners and fonts loading late in the same zone. Fixing what sits above the fold tends to improve rankings and conversion at the same time, which is rare.
How to check it on your site
Screenshot the first viewport
Load your key pages at 1280x800 and 390x844 and capture only what is visible without scrolling. Judge each screenshot cold: can a stranger tell what you sell and what to do next?
Check what your LCP element is
Run PageSpeed Insights and read the LCP element it names. If it is a large decorative image, compress it, serve it as WebP and preload it.
Look for layout shift
In Chrome DevTools open Performance and record a page load. Any movement of above-the-fold content after first paint is CLS you can remove by reserving height for images and ad slots.
Verify the primary action is visible
Your main call to action should be reachable without scrolling on mobile, not buried under three paragraphs of introduction.