Core Web Vitals: What Google Measures and Why It Costs You Sales

Google grades real visits to your site on three measures. They're worth understanding not because Google says so, but because each one maps to a moment where a visitor gives up.

The three measures

• LCP — how long until the main content appears. Under 2.5s.
• CLS — how much the layout jumps while loading. Under 0.1.
• INP — how quickly the page responds to a tap. Under 200ms.

Images are almost always the problem

A 3MB banner uploaded straight from a phone camera will fail LCP on any connection. Serve modern formats at the size actually displayed, set explicit width and height so nothing jumps, and lazy-load anything below the fold. That one pass fixes most sites we audit.

Third-party scripts are the second problem

Chat widgets, multiple analytics tags and ad pixels each add blocking work before your page responds. Audit what's actually loading; most sites carry two or three scripts nobody remembers adding and nobody looks at.

Measure on a real phone

Your site feels fast on your laptop on office WiFi. Test it on a mid-range Android over mobile data, which is how most of your visitors will actually see it. The gap between those two experiences is usually where the lost sales are.