The figures that send a chill down the spine
53% of mobile visitors leave a site that takes more than 3 seconds to load. Amazon calculated that one extra second of delay was costing it $1.6 billion in annual sales. For a small business, proportionally, page speed weighs every bit as heavily.
And since Google’s Page Experience update (2021), page speed has officially been a ranking factor. A website built for SEO cannot afford to be slow. A slow site does not just harm the user experience: it penalizes you directly in the search results.
Core Web Vitals: understanding what Google measures
LCP (Largest Contentful Paint)
The load time of the largest visible element (the main image, a block of text). Target: under 2.5 seconds. Beyond 4 seconds: a poor score, and a ranking penalty.
INP (Interaction to Next Paint)
The site’s responsiveness across every interaction in the visit: clicking a button, opening a menu, typing into a form. Target: under 200 ms. A site that freezes when you click has a poor INP.
INP officially replaced FID (First Input Delay) among the Core Web Vitals in March 2024. FID measured only the delay on the very first interaction; INP, by contrast, assesses responsiveness for the whole length of the visit. If an audit still talks to you about FID and its 100 ms threshold, it is leaning on a metric that has been retired from the program.
CLS (Cumulative Layout Shift)
Visual stability: do the elements of the page move about while it loads? Ads or images that slot in and shove the text aside at the last moment produce a poor CLS, and a frustrating user experience.
The most common causes of a slow website
- Uncompressed images (the number one cause, in 70% of cases)
- Low-end shared hosting with pooled resources
- Too many WordPress plugins (each plugin adds code)
- No caching in place
- Render-blocking JavaScript (analytics, chat, ads)
- Unoptimized web fonts
- No CDN (Content Delivery Network)
How to diagnose your site’s speed
Free, reliable tools:
If the reports leave you baffled, you can have your site’s performance audited in a one-hour session: you walk away with the list of fixes ranked by real gain.
- PageSpeed Insights (pagespeed.web.dev): Google’s detailed analysis, with recommendations
- GTmetrix (gtmetrix.com): a full report with waterfall chart and history
- WebPageTest (webpagetest.org): testing from different locations around the world
Concrete ways to speed up your site
- Compress every image with TinyPNG or Squoosh before uploading it
- Turn on caching (the W3 Total Cache or WP Rocket plugin on WordPress)
- Use a host with NVMe SSDs and cloud infrastructure
- Deactivate and delete the plugins you do not need
- Turn on lazy loading for images (native in WordPress since version 5.5)
- Use a CDN to serve your static assets from nearby servers
- Minify the CSS and the JavaScript
The link between speed and conversion rate
A study by Portent shows that a site loading in 1 second converts 3 times better than a site loading in 5 seconds. For an online store, going from 5 to 2 seconds of load time can, in theory, triple turnover.
If the list looks long, ask us for a prioritized speed plan: we rank the fixes by real gain and by the effort required.
Speed is only one of the levers. The full picture is on the page for our SEO agency in Pau, in south-west France.
Half of the speed gain is decided before the code, on the server: see our managed cloud hosting.
Conclusion
Page speed is not a technical detail reserved for enthusiasts. It is a direct commercial factor, a Google ranking criterion, and a fundamental part of the user experience. Diagnose your site today: it costs nothing, and you can start with the simplest action of all, compressing your images. If the diagnosis turns up heavier work, discover our website plans or have a technician work on your existing site with a support ticket.
