{"id":12015,"date":"2026-07-14T12:00:00","date_gmt":"2026-07-14T12:00:00","guid":{"rendered":"https:\/\/webrim.net\/website-optimisation-speed-core-web-vitals\/"},"modified":"2026-07-14T12:00:00","modified_gmt":"2026-07-14T12:00:00","slug":"website-optimisation-speed-core-web-vitals","status":"publish","type":"post","link":"https:\/\/webrim.net\/en\/website-optimisation-speed-core-web-vitals\/","title":{"rendered":"Website optimisation: speed and Core Web Vitals"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">A slow site loses its visitors before showing them anything at all. It is the most rewarding and the most neglected optimisation: we polish the design, the content, the colours, and then let a page take five seconds to appear on a phone. Speed is not an end-of-project technical detail, it is a condition of conversion and of search visibility. This guide explains what genuinely slows a site down, what Core Web Vitals are without the jargon, and the fixes that really change the outcome.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Speed is about money, not comfort<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The cost of slowness is measured in lost customers. According to Google research, 53% of mobile visitors abandon a page that takes more than three seconds to load, and the probability of a bounce rises by 32% when loading goes from one to three seconds (checked on 15 June 2026). The effect carries through to the sale: a study relayed by Deloitte shows a site loading in one second converts at 3.05%, against 1.08% at five seconds (checked on 15 June 2026).<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In other words, every second gained turns into visitors kept and conversions saved. Performance is not an engineering luxury, it is a direct commercial lever.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Core Web Vitals, without the jargon<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Google measures the loading experience through three indicators, the Core Web Vitals. They sound technical, but each describes a concrete frustration for the visitor.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>LCP<\/strong> measures the time before the main element of the page appears. Plainly: how long before the visitor sees something useful. Aim under 2.5 seconds.<\/li>\n<li><strong>INP<\/strong> measures responsiveness to interaction. Plainly: when the visitor clicks, does the page answer at once or lag.<\/li>\n<li><strong>CLS<\/strong> measures visual stability. Plainly: does content jump around while loading, making the visitor click in the wrong place.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">These three measures have become search signals. A site that looks after them pleases both its visitors and Google, which is rarely a coincidence.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">What slows a site down, and how to fix it<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Images that are too heavy.<\/strong> Often the first cause. Compress them, choose a modern format, size them to how they are actually displayed: an immediate and enormous gain.<\/li>\n<li><strong>Excess code and scripts.<\/strong> Too many extensions, fonts and third-party scripts loading before the content. Trim them, defer whatever is not essential.<\/li>\n<li><strong>No caching.<\/strong> Serving a pre-built version of pages avoids rebuilding everything on each visit. One of the simplest gains there is.<\/li>\n<li><strong>Undersized hosting.<\/strong> A slow server caps everything else. At a certain point, no optimisation makes up for hosting that does not fit.<\/li>\n<li><strong>Third-party scripts left unchecked.<\/strong> Tracking tools, widgets, chat: each one adds weight. Keep what is useful, load the rest after the essentials.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Performance is designed in from the start, not patched afterwards. A site built light, mobile first, starts with an advantage. The subject meets our <a href=\"https:\/\/webrim.net\/en\/mobile-first-ux-good-practice\/\">mobile-first UX good practice<\/a>, where speed is treated as a feature.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>The brief before the brief.<\/strong> Before commissioning an optimisation, measure the real state of your site on a real phone and a real connection, not on the agency fibre. A provider promising a fast site without showing you a starting measurement is selling an intention, not a measurable result.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Measure, then hold it over time<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Performance is measured with free tools that score Core Web Vitals and point to concrete brakes. But an optimisation is never final: a new plugin, a heavy image added, a third-party script, and the page slows again. Speed is watched like security, continuously, not once and for all.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">FAQ: website performance and speed<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Why is my site slow?<\/strong> Most often because of images that are too heavy, an excess of scripts and extensions, no caching, or undersized hosting. A measurement identifies the dominant cause.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>What are Core Web Vitals?<\/strong> Three Google indicators: LCP (time before the main content appears), INP (responsiveness to clicks) and CLS (visual stability). They describe the loading experience and count for search.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>What load time should I aim for?<\/strong> Under three seconds, ideally less. Beyond that, more than half of mobile visitors give up, according to Google (checked on 15 June 2026).<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Does speed affect search visibility?<\/strong> Yes. Core Web Vitals are ranking signals, and a slow site is also a site that loses visitors, which Google observes. Performance and search go together.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><strong>Is an optimisation permanent?<\/strong> No. Every addition of content, plugin or script can slow the site down. Performance is watched over time, like security.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Before you ask for a quote<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Optimising the performance of a site is not a technical whim, it is a lever for conversion and for search. Start from a real measurement, deal with the dominant causes in order, and keep watching over time. Speed is designed in, it is not patched on. A deliverable is not a result.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">In practice, we measure the real state of your site, identify what slows it most, and deal with the brakes in order of impact, with a measurement before and after.<\/p>\n\n\n\n<p class=\"webrim-cta\" style=\"margin:2rem 0\"><a href=\"https:\/\/webrim.net\/en\/quote\/\" style=\"display:inline-block;background-color:#F7C435;color:#0F0F0F;font-weight:600;padding:0.85em 1.6em;border-radius:6px;text-decoration:none\">Request a free quote<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>A slow site loses customers before it shows its content. What genuinely slows a site down, Core Web Vitals explained plainly, and the fixes that change the outcome.<\/p>\n","protected":false},"author":1,"featured_media":10763,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[83,77],"tags":[],"class_list":["post-12015","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-uncategorized-en","category-web-design"],"mb":[],"mfb_rest_fields":["title","gutenberg_elementor_mode"],"_links":{"self":[{"href":"https:\/\/webrim.net\/en\/wp-json\/wp\/v2\/posts\/12015","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/webrim.net\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/webrim.net\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/webrim.net\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/webrim.net\/en\/wp-json\/wp\/v2\/comments?post=12015"}],"version-history":[{"count":0,"href":"https:\/\/webrim.net\/en\/wp-json\/wp\/v2\/posts\/12015\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/webrim.net\/en\/wp-json\/wp\/v2\/media\/10763"}],"wp:attachment":[{"href":"https:\/\/webrim.net\/en\/wp-json\/wp\/v2\/media?parent=12015"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/webrim.net\/en\/wp-json\/wp\/v2\/categories?post=12015"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/webrim.net\/en\/wp-json\/wp\/v2\/tags?post=12015"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}