Core Web Vitals: An Up-to-Date SEO and Performance Guide

Has your site's traffic suddenly dropped, or are you falling behind your competitors? In today's digital world, users abandon websites that don't load and interact within milliseconds in a matter of seconds. The question of what are Core Web Vitals emerges precisely at this point as the most critical concept determining the success of modern websites. These performance metrics, which directly affect Google's search result rankings, sit at the intersection of technical SEO and user experience (UX). In this comprehensive guide prepared by digitalup.tr, we cover all the details that will propel your website to the top.

What are Core Web Vitals? (Quick Summary)

Core Web Vitals is a set of essential performance metrics used by Google to measure user experience on a website. It is based on three main metrics: page loading speed (LCP), interaction responsiveness (INP), and visual stability (CLS), and it is directly a core web vitals seo ranking factor.

What are Core Web Vitals and Why are They Important?

Google Core Web Vitals are a set of standardized signals that quantitatively measure the experience users have when interacting with a web page. The search engine giant aims for users not only to find the information they are looking for but also to access it quickly, smoothly, and securely.

Their Place in Google Rankings and the Impact of Page Experience

With the page experience update, Google placed user-centric signals at the core of its search algorithms. The clearest answer to the question of what is page experience is a combination of HTTPS security, mobile-friendliness, absence of intrusive ads, and Google Web Vitals criteria.

To rank high in search results, content quality alone is not enough; your site's technical infrastructure must also fully meet these signals. A page experiencing performance issues, no matter how high-quality the information it offers, loses value in the eyes of the search engine. Therefore, performance optimization is one of the priority areas in technical SEO processes.

Their Power over E-commerce Conversion Rates (CR) and Bounce Rate

Even small delays in page loading speed can lead to significant revenue losses on e-commerce platforms. Studies have shown that when loading time increases from 1 second to 3 seconds, the bounce rate increases by 32%.

• Increased page load time directly reduces customer loyalty.

• Slow-responding cart and checkout pages increase abandoned cart rates.

• Visual layout shifts cause users to click on the wrong buttons, eroding trust.

When researching how to set up a powerful e-commerce site, the suitability of the infrastructure to speed and user experience standards should be the first consideration.

Key Core Web Vitals Metrics and Target Values

There are three main Core Web Vitals metrics defined and continuously updated by Google:

Largest Contentful Paint (LCP) – Loading Performance

What is LCP? Largest Contentful Paint is a metric that measures the time it takes for the largest image or text block in a page's viewport to load. It represents how long it takes for the user to see the main content on the page. An ideal LCP value should be 2.5 seconds or less.

Interaction to Next Paint (INP) – Interaction and Responsiveness

What is INP? Interaction to Next Paint measures how quickly a site visually responds to all user interactions (clicks, taps, keyboard inputs) on the page. As of March 2024, the previous metric, what is FID (First Input Delay), has been completely retired and replaced by the much more comprehensive INP. While FID only measured the first interaction, INP evaluates interactions throughout the entire page session. The ideal INP value should remain below 200 milliseconds.

Cumulative Layout Shift (CLS) – Visual Stability

What is CLS? Cumulative Layout Shift is a metric that measures unexpected element shifts during the page loading process. For example, if you are reading an article and the text shifts down due to a late-loading advertisement appearing above, or if you intend to click a button but the page shifts and you click somewhere else, this indicates a poor CLS value. An ideal CLS score is below 0.1.

Field Data vs. Lab Data

When analyzing your website's performance, the metrics you encounter are based on two main data sources: Field Data and Lab Data. Understanding the difference between these two types of data is vital for accurate diagnosis.

What is CrUX (Chrome User Experience Report)?

The Chrome User Experience Report (CrUX) is an official dataset that collects anonymous performance data from Google Chrome users under real-world conditions. Google looks at CrUX data, not simulation results, when determining a site's ranking.

Differences Between Lighthouse and RUM (Real User Monitoring)

Lighthouse tools provide instant tests by mimicking a specific device and network speed (Lab Data). However, the high-speed internet environment on a developer's computer does not fully reflect the experience of a user on a mobile network. RUM (Real User Monitoring) systems and CrUX, on the other hand, report delays experienced by real visitors with different devices, locations, and connection speeds.

How to Measure and Analyze Core Web Vitals?

The first step to resolving performance issues is accurate measurement. To perform a Core Web Vitals test, you can use the free tools provided by Google.

Google Search Console "Core Web Vitals" Report

The "Core Web Vitals" section in your Google Search Console panel provides a collective overview of the performance of all URLs on your site, based on field data. Here, you can identify pages that offer a poor experience in groups, separated for mobile and desktop. When conducting website performance analysis, starting by fixing the errors in this panel is the most appropriate method.

Using PageSpeed Insights and Chrome DevTools

To examine the performance of an individual page, you can use the PageSpeed Insights tool. This tool presents real user data (CrUX) at the top and lists laboratory analyses (Lighthouse) containing suggestions to improve site speed SEO effect at the bottom. For more in-depth technical investigations, you can open the Chrome DevTools panel by pressing F12 in your Chrome browser and detailedly examine JavaScript execution times and blocking processes from the Performance tab.

Step-by-Step Core Web Vitals Optimization (Technical Solutions)

After identifying the problems, the Core Web Vitals optimization and website acceleration steps to be implemented are as follows:

LCP Improvement: Image and Server Optimizations

To improve the LCP score, the loading time of the main image needs to be minimized.

• Compress Images and Change Format: Use next-generation formats like WebP or AVIF instead of JPEG/PNG.

• Preload Critical Images: Add the fetchpriority="high" and preload attributes for the largest image on the page to ensure the browser prioritizes this resource:

HTML

<link rel="preload" fetchpriority="high" as="image" href="hero-gorsel.webp" type="image/webp">

INP Improvement: Reducing JavaScript Main Thread Load

For smooth interaction, the browser's Main Thread should not be blocked by long JavaScript tasks.

• Divide Long Tasks: Modularize JavaScript code snippets that take longer than 50 ms.

• Defer Non-essential Code: Add async or defer attributes to non-critical JavaScript files.

• Font Optimization: To prevent the screen from locking up due to late-loading fonts, add font-display: swap; to your CSS code:

CSS

@font-face {
  font-family: 'Open Sans';
  src: url('/fonts/OpenSans.woff2') format('woff2');
  font-display: swap;
}

CLS Improvement: Methods to Prevent Layout Shifts

To prevent elements from shifting abruptly, the browser must be informed about the layout space in advance.

• Define Dimensions for Images: Always include width and height attributes for all <img> and <iframe> tags, or allocate space with CSS:

CSS

img {
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
}

Common Mistakes About Core Web Vitals

Care must be taken against common myths to avoid deviating from the target during performance processes.

"Score Chasing" Risk: Does Getting a PageSpeed Score of 100 Mean Everything?

Focusing on getting a perfect 100 score from the PageSpeed Insights test and completely disabling the site's core functions and scripts ("score chasing") is one of the biggest mistakes. What matters to Google is not getting a score of 100, but rather users having a smooth experience within green threshold values in the real world (Field Data).

Elevate Your Website's Performance to the Top

Strengthening your website's technical infrastructure and providing your users with a smooth, millisecond-level experience is the most effective way to outrank your competitors in search engines. Core Web Vitals optimization is not just an effort to boost scores; it's a long-term investment that directly increases customer satisfaction, conversion rates, and brand credibility.

To increase the power of your digital assets in search engines, eliminate technical errors, and bring your performance to the green zone, discover the professional solutions from the digitalup.tr team. Contact us now to unleash your site's potential.