Google does not just check whether your site loads fast — it measures three specific things, from real visitors, and they affect rankings. Here is what they mean in plain language.
LCP — how fast the main thing appears
Largest Contentful Paint: how many seconds until the biggest element (usually the hero image or heading) shows. Target: under 2.5 seconds.
Usual culprit: a huge header image. Fix: compression, correct dimensions, WebP, and do not lazy-load the main image — it must come first.
INP — how fast it reacts
Interaction to Next Paint: you click a button, how long until something happens. Target: under 200 milliseconds.
Culprit: too much JavaScript (plugins, chats, pixels, banners). Every add-on eats into this. Fix: fewer plugins, defer non-urgent scripts.
CLS — does the content jump
Cumulative Layout Shift: you go to click and the page moves, so you click something else. The most irritating feeling online. Target: under 0.1.
Culprit: images without set dimensions, banners injected after load, swapping fonts. Fix: width and height on every image, reserved space for dynamic elements.
Where to see them
- PageSpeed Insights — paste an address, get a score plus concrete advice
- Search Console → Experience — real data from your visitors across many pages (more accurate than the test)
Look at the mobile results. Desktop is almost always fine and does not tell the truth.
Realistically
Do not chase 100/100 — diminishing returns. The goal is green on the three Vitals and a site that feels fast. Nobody notices 75 versus 95; everybody notices 30 versus 75.
The biggest wins in order
- Compressed images (biggest effect, least effort)
- Caching
- A modern PHP version
- Fewer plugins
- Good hosting — the foundation; on a weak server all the above is makeup