Core Web Vitals, explained without the jargon.

Core Web Vitals get talked about as an SEO checkbox, which undersells them. They are Google's attempt to measure something real: whether a page loads fast, responds when you touch it, and stays visually stable while you use it. Fixing them improves rankings, but it improves conversion rates for the exact same reason.

The three metrics

Largest Contentful Paint (LCP) measures how long the biggest visible element — usually a hero image or heading — takes to render; under 2.5 seconds is good. Interaction to Next Paint (INP) measures how responsive the page feels when a visitor clicks, taps or types; under 200ms is good. Cumulative Layout Shift (CLS) measures how much content jumps around as the page loads; under 0.1 is good.

Why they affect rankings and conversions

Google uses page experience as one ranking signal among many, so Core Web Vitals alone will not rescue a page with no relevant content. But the same issues that hurt these scores — slow loading, sluggish interactions, jumpy layouts — are exactly the things that make a real visitor leave before converting. The ranking effect and the conversion effect share a root cause.

Where sites usually lose points

Unoptimised hero images and background videos are the most common LCP killer. Render-blocking JavaScript and heavy third-party scripts — chat widgets, ad tags, marketing pixels — tend to wreck INP. CLS is usually caused by ads, web fonts, or embeds (reviews widgets, maps) that load late and shove content down after the visitor has already started reading.

Fixing it without a rebuild

Most of this is fixable incrementally: compress and lazy-load images below the fold, defer non-critical third-party scripts until after first interaction, reserve layout space for anything that loads asynchronously, and serve static assets through a CDN with proper caching headers. A full rebuild is rarely the first move — a targeted performance pass usually is.

— FAQ

Frequently asked questions

• What tool should I use to check my scores?+

  Google Search Console's Core Web Vitals report shows real-world "field" data from actual visitors; PageSpeed Insights gives you an instant "lab" test — use both, since they can disagree.

• Do Core Web Vitals matter for e-commerce specifically?+

  Yes, often more — catalogue-heavy pages, product image galleries and the third-party trackers common in e-commerce make these scores harder to hit, and slow product pages have a direct, measurable cost in lost sales.

• How much of a ranking factor are they really?+

  One signal among many — relevance and content still dominate. But a genuinely broken page experience caps how well everything else you do can perform.