Core Web Vitals: the metrics Google cares about

What are Core Web Vitals?

Core Web Vitals are three metrics Google uses to measure the user experience of your website. Since 2021 they have been an official ranking factor. Poor scores mean a lower position in Google.

The 3 metrics

LCP, Largest Contentful Paint

What it measures: how quickly the largest visible element (usually an image or heading) loads.

Score	Rating
< 2.5s	Good (green)
2.5 - 4s	Needs improvement (orange)
> 4s	Poor (red)

How to improve LCP

Optimise images (WebP, correct dimensions)
Use fast hosting
Avoid render-blocking JavaScript
Lazy load images that aren't immediately visible

INP, Interaction to Next Paint

What it measures: how quickly the page responds when a visitor clicks, taps or types.

Score	Rating
< 200ms	Good (green)
200 - 500ms	Needs improvement (orange)
> 500ms	Poor (red)

How to improve INP

Minimise JavaScript
Break up long tasks
Avoid heavy event handlers
Use a lightweight framework (like SvelteKit)

CLS, Cumulative Layout Shift

What it measures: do elements on the page shift while it loads? Think of text jumping sideways because an ad or image suddenly loads in.

Score	Rating
< 0.1	Good (green)
0.1 - 0.25	Needs improvement (orange)
> 0.25	Poor (red)

How to improve CLS

Always give images a width and height
Reserve space for ads and embeds
Load fonts correctly (font-display: swap)
Avoid content that gets injected later

Where to check your scores

PageSpeed Insights: the official Google tool
Search Console: real user data
Our free SEO check: a report straight away

Why do WordPress sites often score poorly?

WordPress sites typically load 15-30 plugins. Each plugin adds JavaScript and CSS. The result:

LCP of 4+ seconds
High CLS from late-loading elements
Slow INP due to too many scripts

How we approach it

At Friday Webs we build with SvelteKit, a framework that ships minimal JavaScript to the browser. The result:

LCP: under 1 second
INP: under 50ms
CLS: 0

No plugins, no clutter, no compromises.