Since Google's Page Experience update, Core Web Vitals have been official ranking signals — meaning they directly affect where your website appears in search results. Yet most website owners have never heard of them, let alone measured or optimized them. If your competitors are taking Core Web Vitals seriously and you are not, they are gaining a measurable advantage in organic search.

Here is everything you need to understand and act on.

What are Core Web Vitals?

Core Web Vitals are a set of real-world performance metrics that measure how users actually experience your website — not just how fast data is transferred, but how quickly content appears visually, how stable the layout is, and how responsive it is to interaction.

LCP — Largest Contentful Paint

LCP measures the time it takes for the largest visible element on the page (usually the hero image or main headline) to fully render from when the user first navigates to the URL. A good LCP score is under 2.5 seconds. Between 2.5 and 4.0 seconds needs improvement. Over 4.0 seconds is poor. The most common causes of poor LCP are: slow server response times, render-blocking CSS or JavaScript, large unoptimized images, and poor caching.

CLS — Cumulative Layout Shift

CLS measures visual stability — specifically, how much the page layout unexpectedly shifts during loading. You have experienced this when you go to tap a button and the page shifts at the last moment, causing you to tap the wrong element. Frustrating? Google measures exactly this and penalizes it. A good CLS score is below 0.1. Common causes: images and embeds without explicit dimensions, ads that inject themselves into the layout, and web fonts that cause text to re-render.

INP — Interaction to Next Paint

INP replaced FID (First Input Delay) as of March 2024. It measures the responsiveness of your page to all user interactions throughout the page lifecycle — taps, clicks, key presses. A good INP is below 200 milliseconds. Poor INP is caused by heavy JavaScript execution that blocks the main thread, particularly in complex single-page applications.

How to measure your Core Web Vitals

Use Google Search Console (the Core Web Vitals report shows real user data from the Chrome User Experience Report), Google PageSpeed Insights (provides both lab and field data for any URL), and Lighthouse in Chrome DevTools (an in-depth audit with specific recommendations).

How to improve your scores

For LCP: use a CDN, optimize and compress images, implement preload for hero images, eliminate render-blocking resources, and use efficient cache policies. For CLS: always set explicit width and height attributes on images and embeds, reserve space for ads and dynamically injected content, and use font-display: swap with font size adjustments. For INP: reduce JavaScript execution time, break long tasks into smaller chunks using scheduler APIs, defer non-critical scripts, and use web workers for CPU-intensive operations.

At Wiztechit, performance optimization is a core part of every website project we deliver. We also offer standalone performance audits and optimization services for existing websites. Contact us for a free Core Web Vitals assessment of your current site.