The three Core Web Vitals
- LCP (Largest Contentful Paint) — how long until the biggest visible element (usually a hero image or headline) finishes loading. Target: under 2.5 seconds.
- INP (Interaction to Next Paint) — how quickly the page responds after a tap or click. Target: under 200 milliseconds.
- CLS (Cumulative Layout Shift) — how much content jumps around while loading (the classic "I tried to tap a button and an ad loaded under my finger" problem). Target: under 0.1.
Google measures real user experience across three dimensions, not just raw load time.
Why it matters especially in India
A meaningful share of Indian traffic still arrives over 4G with variable signal quality, not fibre broadband. A homepage built and tested only on a fast office wifi connection can feel dramatically slower — or fail to load key content at all — on a real customer's phone. Test on throttled mobile connections, not just your desk.
The highest-leverage fixes
In rough order of impact for a typical small business site:
- Compress and correctly size images (a 4MB hero photo is the single most common cause of a slow LCP).
- Reserve space for images and ads before they load, to prevent layout shift.
- Defer non-critical JavaScript (chat widgets, tracking scripts) so it does not block the first render.
- Use a fast, well-configured host — no amount of front-end optimisation fixes a slow server.
Run PageSpeed Insights on your homepage right now. It gives real Core Web Vitals data from actual visitors, not just a lab simulation.