Core Web Vitals

What Are Core Web Vitals?

Core Web Vitals are a set of performance metrics defined by Google to measure the quality of the real-world user experience on a web page. Unlike technical benchmarks that developers test in controlled environments, Core Web Vitals are based on data collected from actual users visiting the site — reflecting how fast, interactive, and stable the page feels to people on real devices and real connections.

Google incorporated Core Web Vitals into its ranking algorithm as part of the Page Experience update. They are not the dominant ranking signal, but they are a confirmed factor, and poor performance can suppress rankings in competitive searches.

The Three Metrics

Largest Contentful Paint (LCP) measures loading performance. Specifically, it records the time from when the user initiates navigation to when the largest image or text block in the viewport has finished rendering. The threshold is:

• Good: under 2.5 seconds
• Needs improvement: 2.5 to 4 seconds
• Poor: over 4 seconds

LCP is primarily affected by server response time, render-blocking resources, and the size of hero images or above-the-fold content.

Interaction to Next Paint (INP) measures interactivity — the delay between any user interaction and the browser's next visual response. INP replaced First Input Delay (FID) in March 2024 because it captures all interactions during a session, not just the first. The threshold is:

• Good: under 200 milliseconds
• Needs improvement: 200 to 500 milliseconds
• Poor: over 500 milliseconds

Poor INP is typically caused by heavy JavaScript or long tasks on the main thread.

Cumulative Layout Shift (CLS) measures visual stability. It quantifies how much page elements shift unexpectedly as the page loads — when an image loads and pushes text down, or a banner appears and moves a button the user was about to tap. The threshold is:

• Good: under 0.1
• Needs improvement: 0.1 to 0.25
• Poor: over 0.25

CLS is commonly caused by images and ads without reserved dimensions, web fonts that swap during load, and dynamically injected content.

Why Core Web Vitals Matter for Local Businesses

Local businesses receive a disproportionate share of mobile traffic from users looking for a location, hours, or a phone number. Mobile devices are more resource-constrained than desktops, and a page that feels slow or unstable creates friction exactly when a potential customer is closest to making a decision.

Poor performance also drives higher bounce rates. A user who leaves a slow page immediately is a missed conversion, and engagement signals feed back into Google's quality assessment over time.

How to Measure Core Web Vitals

Google Search Console provides real-user data in the Core Web Vitals report, categorized by page group. This is the most authoritative source because it reflects actual visitors.

PageSpeed Insights provides both lab and field data for individual URLs, along with specific recommendations for improvement. Lighthouse in Chrome DevTools offers lab-based measurement during development.

An audit through dilypse.localscan.io includes Core Web Vitals data as part of a broader website health check, placing performance scores alongside your NAP consistency, reviews, and schema markup for a complete local SEO picture.