If you've ever run your website through Google's PageSpeed Insights, you've probably seen three acronyms — LCP, INP and CLS — and a lot of red, orange and green. These are Core Web Vitals, and they describe how your site feels to a real person using it.
You don't need to become a developer to understand them. Here's what each one means.
LCP — how fast the main content appears
Largest Contentful Paint measures how long it takes for the biggest thing on the screen — usually a hero image or headline — to show up.
When LCP is slow, visitors stare at a half-empty page and wonder if something is broken. The usual causes are oversized images, slow servers and fonts or scripts that block the page from rendering.
INP — how quickly the page responds
Interaction to Next Paint measures the delay between someone tapping a button or menu and the page visibly responding.
A poor INP makes a site feel sluggish or "stuck", especially on mid-range phones. It's usually caused by heavy JavaScript doing too much work at once.
CLS — whether things jump around
Cumulative Layout Shift measures how much the layout moves while the page loads. You've experienced bad CLS if you've ever gone to tap a link and an ad or image pushed it out of the way at the last moment.
It's typically fixed by reserving space for images, embeds and banners before they load.
Why this matters for your business
- Visitors stay longer on pages that load quickly and behave predictably.
- Search engines use these signals as part of how they assess page experience.
- Mobile users benefit most — and for many businesses, they're the majority of visitors.
What to do next
- Test your key pages — home, services and contact — in PageSpeed Insights.
- Note which of the three metrics is in the red.
- Fix the biggest problem first; one improvement often helps the others.
Core Web Vitals aren't about chasing a perfect score. They're a practical checklist for making your website pleasant to use. If your results look worrying, we're happy to review them with you.
- #Performance
- #SEO
- #Core Web Vitals