Since 2021, Google has been incorporating the Core Web Vitals in its ranking criteria. These technical performance metrics have become an SEO signal in their own right, just like content quality. Many Belgian business websites still ignore them, allowing their competitors to gain ground. Here’s what Core Web Vitals are, why they matter, and how to improve them.
Understanding the three Core Web Vitals metrics
The Core Web Vitals These comprise three metrics that Google considers to be the most representative of the actual user experience on a website. They measure, respectively, page load speed, responsiveness and visual stability.
LCP, FID and CLS: what they measure
Le LCP (Largest Contentful Paint) measures the load time of the largest visible element. Google recommends less than 2.5 seconds. The’INP (Interaction to Next Paint), which replaced the FID in 2024, measures responsiveness during interactions. The CLS (Cumulative Layout Shift) measures unexpected visual shifts during loading – those elements that move and cause users to click in the wrong place. A good CLS score is less than 0.1.
How Google uses these metrics in its algorithms
Given equivalent content, a faster and more stable website will have an advantage over a slow one. For competitive search queries, this difference can mean a difference of several positions in the search results.
The direct impact of performance on visitor behaviour
Technical performance is not just a signal for Google: it directly influences user behaviour, and therefore the metrics that Google monitors to refine its rankings.
The bounce rate increases as the loading time increases
A loading time of more than three seconds leads to a significant increase in the bounce rate. A user who leaves immediately sends a negative signal to Google. Improving the LCP mechanically improves the bounce rate, and by extension the signal sent to Google regarding the page’s quality.
Visual stability affects trust and conversion rates
A website where elements move whilst loading leads to click errors and users abandoning the page. Fix the CLS simultaneously improves the user experience and the behavioural metrics tracked by Google.
The most common technical causes of a poor score
Most Core Web Vitals issues have identifiable and fixable technical causes. One technical and SEO audit enables them to be mapped out precisely before prioritising the corrections.
Unoptimised images and blocking resources
Images that are too large or that load at the wrong time are the most common cause of a poor LCP. Loading large JavaScript files before the page is rendered blocks the display. A front-end consultant is proficient in code splitting, image optimisation and lazy loading; iterates complies with Core Web Vitals standards across all its front-end projects.
Hosting that is under-specced or incorrectly configured
Server response time (TTFB) is a prerequisite for a good LCP. Shared or poorly scaled hosting results in response times that undermine all optimisation efforts, regardless of any adjustments made to the code.
How to improve your Core Web Vitals in practice
Improving Core Web Vitals doesn’t happen overnight, but it is a methodical process. The priority actions are well known and well documented.
Use a CDN and cache content intelligently
A CDN delivers resources from servers located close to users, reducing latency. Caching static resources prevents them from having to be reloaded on every visit. These two optimisations quickly reduce the LCP without altering the code. The website maintenance d’iterates incorporates the monitoring of performance scores and these optimisations over time.
Audit and correct visual discrepancies
The CLS can be corrected by specifying explicit dimensions for images, avoiding the insertion of content above existing content, and preloading fonts. These corrections are often minor in terms of code, but their impact on the score is immediate.
Incorporating performance right from the website design stage
Reworking an existing website is always more expensive than designing it properly from the outset. Technical performance must be a design criterion, not something to be rectified after the fact.
Redesigning a website plagued by performance issues
For a website whose Core Web Vitals scores are structurally poor due to outdated technical choices – such as an overloaded WordPress theme, too many plugins, and unoptimised code – a redesign or modification of the existing website A performance-focused approach is often more cost-effective in the long term than a series of superficial fixes.
Tracking changes to Google’s ranking criteria over time
The Core Web Vitals are evolving – the shift from FID to INP is a case in point. The SEO in the age of generative AI introduces new criteria – crawlability by AI agents and information density – which complement the Core Web Vitals and redefine what constitutes a high-performing website for search engines.
Improve your website’s performance with iterates
iterates supports Brussels-based SMEs in auditing and optimising their web performance, from analysing Core Web Vitals through to implementing technical fixes, delivering measurable results in Google rankings.
