Core Web Vitals for business websites

Google publishes three metrics describing how a page feels to use. They are worth understanding because they measure the things visitors actually notice.

The three measures

Largest Contentful Paint. How long until the main content appears. Target under 2.5 seconds. Usually a large unoptimised image, a slow server response, or fonts blocking the render.

Interaction to Next Paint. How quickly the page responds when someone clicks. Target under 200 milliseconds. Usually too much JavaScript occupying the browser.

Cumulative Layout Shift. How much the page jumps around while loading. Target under 0.1. Usually images without dimensions, or a banner injected above content that has already been read.

That last one causes the most irritation per occurrence — everyone has tapped the wrong thing because the page moved.

The fixes with the best return

• Serve images properly. Modern formats, correct dimensions, lazy loading below the fold. On most business sites this alone fixes the first metric.
• Set width and height on every image. One attribute pair, and the layout stops jumping.
• Remove scripts nobody uses. Old analytics, an abandoned chat widget, three tag manager containers.
• Self-host fonts, and subset them. External font requests block rendering; a subset removes characters you never use.
• Cache aggressively at the edge. Static pages served from a content delivery network respond in tens of milliseconds regardless of where the visitor is.

Measure the right thing

Laboratory tools give a clean score on a fast connection. Field data reflects real visitors on real phones on real networks. When the two disagree, the field data is correct.

Where it actually pays

A business site earns its keep through enquiry forms. Every second of delay loses a fraction of the people who intended to fill one in, and mobile visitors on a weak connection are the least patient. The ranking benefit is real but secondary to that.

Do not chase a perfect score. Get into the green thresholds, confirm the form works quickly on a mid-range phone, and spend the remaining effort on the content.

We build to these standards in web development.