Why Is My Website Slow? 7 Common Causes and How to Fix Them

How Slow Is Too Slow?

Google considers any page that takes longer than 2.5 seconds to show its main content as "slow." But visitor expectations are even harsher — 53% of mobile users abandon a site that takes more than 3 seconds to load. Every extra second costs you roughly 7% of conversions.

The 7 Most Common Causes

1. Unoptimised Images

This is the number one cause of slow websites. A single uncompressed photograph can be 5MB — more than your entire page should weigh. Convert images to WebP or AVIF format, resize them to the actual display size, and use lazy loading so off-screen images don't load until needed.

2. Cheap or Overloaded Hosting

Your hosting is the foundation of your website's speed. Shared hosting plans that cost a few pounds a month pack hundreds of sites onto one server. When other sites on your server get traffic spikes, your site slows down too. If your site is slow everywhere (not just on certain pages), hosting is likely the bottleneck.

3. Too Much JavaScript

Every JavaScript file has to be downloaded, parsed, and executed before your page is fully interactive. Third-party scripts are the worst offenders — analytics, chat widgets, social media embeds, and ad trackers can add seconds to your load time. Audit your scripts and remove anything you're not actively using.

4. Render-Blocking CSS

The browser can't show your page until it's downloaded and processed all your CSS files. If you have large stylesheets or multiple CSS files loading in the head of your page, the browser has to wait for all of them before rendering anything. Inline your critical CSS and defer the rest.

5. Too Many Web Fonts

Custom fonts look great but each font file is typically 20-100KB. If you're loading multiple weights and styles (regular, bold, italic) across two or three font families, that's potentially 500KB+ of fonts alone. Stick to one or two font families and only load the weights you actually use.

6. Too Many Redirects

Each redirect adds a full round trip to your server before the page even starts loading. Common culprits: redirecting HTTP to HTTPS, then www to non-www (or vice versa), then to a trailing slash. That's three redirects before your page loads. Consolidate them into a single redirect.

7. No Browser Caching

Without caching headers, the browser downloads every file fresh on every visit. Setting proper cache-control headers means returning visitors load your site almost instantly because images, CSS, and JavaScript are stored locally. This is one of the easiest performance wins.

Quick Wins

Find Out What's Slowing Your Site Down

The first step is measuring. A speed test shows you exactly where the bottlenecks are — which files are largest, which requests take longest, and what your Core Web Vitals scores look like. Without data, you're guessing.