⚙️What are Core Web Vitals and how do they affect your website

What are Core Web Vitals

In recent years, Google has increasingly focused on user experience as a fundamental factor for ranking websites in search results. In this context, the Core Web Vitals were born: a set of key metrics officially introduced by Google to measure the quality of a website's loading, interactivity, and visual stability experience. These are not just technical numbers, but crucial elements that determine whether your site is efficient, competitive, and optimized for SEO. In 2025, ignoring the Core Web Vitals literally means losing traffic, customers, and online growth opportunities.

The Core Web Vitals are three: LCP (Largest Contentful Paint), FID (First Input Delay), and CLS (Cumulative Layout Shift). Each of these parameters represents a fundamental aspect of the user experience.

LCP measures the time it takes for the main content element (such as an image or block of text) to be fully visible to the user. It is an indicator of "perceived speed": if the user has to wait too long, they will think the site is slow or stuck. Google considers a good LCP value to be within 2.5 seconds. Exceeding this threshold can seriously penalize a site's visibility in search results.

FID measures the delay between the user's first interaction (click, touch, keyboard) and the moment when the browser is actually able to respond. It is a metric of responsiveness: if the site doesn’t respond immediately, the user experience becomes frustrating. The optimal value according to Google is under 100 milliseconds. A site that takes too long to react gives a sense of slowness and inefficiency, with direct impacts on bounce rate.

CLS evaluates how much the page layout shifts during loading. Have you ever clicked a button and suddenly the page “jumped,” making you press the wrong one? This is the classic effect of high CLS. A visually stable site conveys professionalism and reliability. The value recommended by Google is less than 0.1.

In 2025, these indicators are no longer just suggestions: they are an integral part of Google’s ranking algorithm. Sites that do not achieve good scores in the Core Web Vitals are considered less relevant, even if they have great content or attractive design. This means that even the most beautiful site in the world can end up at the bottom of search results if it is slow, unstable, or unresponsive.

Optimizing Core Web Vitals requires technical skills, but also a strong focus on site structure from the design phase. Image loading must be optimized using modern formats like WebP or AVIF, the HTML structure must be clean and semantic, animations light and controlled, fonts loaded asynchronously. It is necessary to use caching systems, CDNs, lazy loading, code minification, and constant testing using tools such as Google PageSpeed Insights, Lighthouse, GTmetrix, or Chrome DevTools.

WordPress, for example, can be perfectly compatible with Core Web Vitals requirements, but only if properly configured: lightweight theme, well-chosen plugins, performant hosting. The same goes for any other platform — Webflow, Tilda, React/Next.js — no technology guarantees good scores on its own. It’s the optimization and technical awareness that make the difference.

Mobile also plays a fundamental role. In 2025, most web traffic comes from mobile devices. Core Web Vitals are primarily measured on these experiences. A site that works perfectly on desktop but has a neglected mobile experience risks being penalized. A mobile-first design is needed, tested on real screens, with a touch-friendly UI and loading times under 2 seconds even on 4G.

The direct influence of these parameters on conversion rates must also be considered. A slow or unstable site not only loses positions on Google but scares users away, who might abandon before filling out a form, reading an offer, or purchasing a product. Improving Core Web Vitals also means improving user experience, customer trust, and business results.

For this reason, at Studio Web we have integrated Core Web Vitals analysis as an essential part of every project. Every site we create is tested and optimized to offer not only visual beauty but also concrete, measurable performance aligned with modern Google standards. We work on every technical detail, from initial load to dynamic behavior, to ensure the user perceives the site as smooth, fast, and pleasant to use.

Core Web Vitals are not a passing trend. They reflect what users expect today from a quality digital experience. Investing in their improvement means building a solid, competitive site ready to generate lasting results.

📊 Optimizing Core Web Vitals: practical cases, tools, and tangible benefits for your business

Understanding Core Web Vitals is just the first step. The real value for a business comes when you actively work on optimization, constantly monitor real site performance, make targeted technical improvements, and above all, measure results. In an increasingly competitive digital environment, even reducing a page's load time by half a second can mean hundreds of additional conversions per month. This is not theory, but statistics.

According to a study published by Google, reducing the time for the first visible content to load from 2.5 to 1.5 seconds can increase conversions by 12% in e-commerce and lead generation. Improving CLS from 0.25 to less than 0.1 reduces incorrect clicks by 20% and increases average time spent on the site. For this reason, large companies — but also small businesses with vision — are starting to include Core Web Vitals in their strategic KPIs.

But how does all this translate into practical action?

One of the most common mistakes in corporate sites is the excessive use of heavy elements on the homepage: sliders with high-resolution images, unoptimized external scripts, fonts loaded from multiple sources, and unnecessary plugins. These elements critically slow down LCP, even when hosting infrastructure is good. The solution is not to remove everything but to choose wisely: use WebP images optimized with tools like Squoosh or TinyPNG; load fonts locally and avoid multiple fallbacks; minify CSS and JavaScript, possibly with automatic tools built into modern builders.

Animations also play an ambiguous role. Many sites use entrance effects, dynamic movements, and popup sections. If overdone or built with heavy JavaScript, they can cause layout shifts during loading, worsening CLS. Better to use smooth, predefined CSS transitions, with a progressive loading logic for visual elements. Every second, every shift, every “jump” has a direct impact on perceived quality.

Tools like Google PageSpeed Insights and Lighthouse are essential for quickly analyzing issues, but often are not enough. For deeper work, it’s advisable to monitor metrics in real-time with Google Search Console (Experience → Page Experience report) or professional tools like SpeedCurve, Calibre, WebPageTest, or Raygun. These tools show how the site behaves on real mobile connections, on low-end devices, and slow networks — simulating real users, not just lab benchmarks.

Another strategic element is caching and smart use of a Content Delivery Network (CDN). A CDN distributes site content through various servers around the world, drastically reducing load times for users far from the main server. Cloudflare, Netlify, Vercel, and StackPath are among the most popular options, often integrable in a few clicks even with WordPress or Shopify. Combined with a good cache configuration (both server-side and client-side), this can improve LCP by 40–50%.

In our daily work at Studio Web, we’ve seen many cases where interventions on Core Web Vitals produced tangible results in a matter of weeks. For example, a site for a construction company suffering from a 4.8-second LCP improved to 1.9 seconds after homepage refactoring, removing six redundant plugins, and adopting system-native fonts. In less than two months, organic visits increased by 32%, and average session duration grew by 47%.

Work on these metrics is never “one and done.” Google continually updates its algorithms, browsers evolve, and standards change. The Core Web Vitals themselves are evolving: in 2024, Interaction to Next Paint (INP) was introduced to replace FID, measuring real responsiveness throughout the session. In 2025, this metric will become increasingly present in reports and ranking criteria. A continuous process of monitoring, updating, and reviewing is needed, with professional tools and expert people.

Finally, the impact on branding and business perception must also be emphasized. A fast, smooth, and stable site communicates value, reliability, and attention to detail. The visitor perceives this unconsciously: a site that opens immediately and responds precisely to touch creates trust. A site that loads slowly, jumps graphically, freezes, or forces users to wait conveys the image of an outdated, unresponsive company that lags behind.

Optimizing Core Web Vitals is no longer a matter of “performance for techies,” but a conscious act of digital marketing. It is a tool to increase conversions, improve ranking, stand out from the competition, and offer your users an experience truly worthy of their expectations. In a world where every millisecond counts, your site’s quality is measured not only by how it looks… but by how it behaves.