Does website speed really matter?

Yes — measurably so. Google research found that 53% of mobile visitors abandon a page if it takes more than three seconds to load. Every additional second of delay increases the chance of someone leaving before they've seen anything.

Speed also affects your search rankings. Page loading performance is a confirmed Google ranking signal, and slow sites tend to rank lower than faster alternatives with similar content quality.

So if your site feels slow, it's worth understanding why. The causes are usually straightforward — and so are the fixes.

Cause 1: Unoptimised images

Most common cause

Images that are too large or in the wrong format

A full-resolution photo from a camera or phone is typically 5–20 MB. Served directly on a web page, that single image can take 10–30 seconds to load on a mobile connection. Most websites have dozens of images. If none are optimised, the page will be painfully slow.

What to do: resize images to the actual display dimensions (there's no reason a thumbnail should be 4,000 pixels wide), convert them to WebP or AVIF format (which are 30–60% smaller than JPEG or PNG at equivalent quality), and compress them before uploading. Tools like Squoosh, ImageOptim, or Cloudflare Images can automate much of this. Also ensure images below the fold use lazy loading so they only download when needed.

Cause 2: Poor hosting

Your hosting is the foundation everything sits on. A slow server means a slow site — no amount of optimisation on the front end can fix a server that takes two seconds just to respond.

The metric to look at here is Time to First Byte (TTFB) — how long it takes the server to start sending data after a request. A good TTFB is under 200 ms. Many budget shared hosting plans regularly exceed 1,000 ms, especially during peak times when the server is overloaded with other customers' traffic.

What to do: choose a hosting provider with a good performance track record. For UK businesses, I use and recommend Hosterion — servers are fast, UK-based, and TTFB is consistently under 200 ms. Avoid the cheapest shared plans from large generic hosts; the price saving rarely justifies the performance penalty.

Cause 3: Too many plugins and scripts

WordPress sites in particular tend to accumulate plugins over time — a chat widget here, a slider there, a cookie consent tool, an analytics platform, a social sharing bar. Each plugin adds HTTP requests, CSS files, and JavaScript that the browser must download and process before the page can be shown.

It's not unusual to find a WordPress site loading 80–100 separate files. That alone can add several seconds to load time, even if each individual file is small.

What to do: audit what's actually being used. Remove plugins that provide minimal value. Replace heavy plugins with lighter alternatives or native solutions. Load scripts asynchronously or defer them so they don't block page rendering. Consider whether some features are worth the performance cost at all.

Cause 4: No caching or compression

Without caching, every visitor to your site triggers a full database query and page build from scratch — even if nothing has changed since the last visitor a second ago. Without compression, files are transferred at full size when they could be 70–80% smaller.

Both are easy wins that have an immediate, measurable impact on speed.

What to do: enable Gzip or Brotli compression on your server (most modern hosts support this in their control panel). Implement browser caching headers so returning visitors don't re-download static assets. If you're on WordPress, a caching plugin such as WP Rocket or LiteSpeed Cache handles most of this automatically. On a custom site, these are typically configured at the server level.

Cause 5: Render-blocking resources

If large CSS or JavaScript files are loaded in the <head> of your page, the browser must download and process them before it can display anything. This is called render-blocking — the page is ready to show content, but it's waiting for scripts and stylesheets to finish loading first.

What to do: load JavaScript with defer or async attributes so it doesn't block rendering. Move non-critical CSS to load after the page has painted. Inline the minimal CSS needed for above-the-fold content so the page can render immediately. PageSpeed Insights will flag any render-blocking resources and explain which files are responsible.

How to measure your site's speed

You don't need to guess. These tools give you accurate, actionable data:

  • Google PageSpeed Insights (pagespeed.web.dev) — the most important tool. Gives you real user data and specific recommendations. Run it on your homepage and your most important landing pages.
  • GTmetrix — detailed waterfall charts showing every file that loads, in order. Makes it easy to see which resources are the biggest problem.
  • WebPageTest — the most in-depth option. Choose a test location close to your audience, select a realistic device and connection speed, and get a full breakdown including a visual filmstrip of how the page loads over time.

Always test on mobile. Most of your visitors are on phones, often on 4G rather than WiFi. PageSpeed Insights tests both desktop and mobile — the mobile score is usually significantly lower and is the one that matters most for SEO.

What to do next

If your PageSpeed score is below 70 on mobile, there's meaningful room for improvement. Start with images — that alone often solves 50% of the problem. Then look at your hosting if TTFB is high.

For a deeper look at how speed connects to search rankings, read what technical SEO actually covers.

If you'd like a site that's built fast from the ground up rather than retrofitted, take a look at how I approach web design or get in touch to discuss your project.