Slow loading progress bar on a laptop screen with a stopwatch beside it
# website performance# troubleshooting

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

Website speed matters. Visitors expect pages to load quickly, and if they don't, they leave. Search engines also factor speed into rankings — a slow site can quietly hurt your visibility without any obvious error message to point to.

The tricky thing about slow websites is that the cause isn't always obvious. Here are the most common culprits and what to do about each one.

1. Unoptimised Images

Images are usually the biggest contributor to page weight. A single uncompressed high-resolution photo can be several megabytes — your entire page HTML might be just a few kilobytes.

Fix:

  • Compress images before uploading. Tools like Squoosh or TinyPNG reduce file size dramatically with minimal visible quality loss
  • Use modern formats: WebP is significantly smaller than JPEG or PNG at the same quality
  • Set correct image dimensions — don't serve a 2000px wide image for a 400px thumbnail
  • Add loading="lazy" to images below the fold so they don't block initial page load

2. No Caching

Without caching, every visitor triggers the server to rebuild the page from scratch — querying the database, running PHP or Python, assembling the HTML — every single time.

Fix:

  • Browser caching: Set appropriate Cache-Control headers on static assets so browsers don't re-download them on repeat visits
  • Server-side caching: Use a full-page cache (like Nginx FastCGI cache or a WordPress caching plugin) so the server only builds each page once
  • Object caching: Use Redis or Memcached to cache database query results

A well-cached page that would take 800ms to generate dynamically can load in under 50ms from cache.

3. Too Many HTTP Requests

Every file on your page — every image, script, stylesheet, font — is a separate HTTP request. Each one adds overhead, especially on HTTP/1.1 connections.

Fix:

  • Combine and minify CSS and JavaScript files
  • Use an icon font or SVG sprites instead of individual small images
  • Remove unused plugins, scripts, and stylesheets
  • Load third-party scripts (analytics, chat widgets, ads) asynchronously so they don't block page rendering

4. Slow Server Response Time (TTFB)

Time to First Byte (TTFB) is how long it takes the server to start sending a response after receiving a request. A high TTFB means slow hosting, database bottlenecks, or inefficient application code.

Check your TTFB with Chrome DevTools (Network tab, look at the "Waiting" time on the first document request). Anything over 200ms is worth investigating.

Fix:

  • Upgrade your hosting plan or move to a faster host
  • Add server-side caching as described above
  • Optimise slow database queries
  • Use a CDN to serve responses from a location closer to the visitor

Our guide to what is time to first byte covers this in more depth.

5. No CDN (Content Delivery Network)

If your server is in London and a visitor is in Sydney, every request has to travel halfway around the world and back. Latency alone can add hundreds of milliseconds to every page load.

Fix: Use a CDN like Cloudflare, Fastly, or AWS CloudFront. A CDN caches your content on servers around the world and serves it from the nearest location to each visitor. Even on a free tier, Cloudflare makes a noticeable difference to global load times.

6. Render-Blocking JavaScript and CSS

If your page loads large JavaScript or CSS files in the <head> before rendering begins, visitors see a blank page until those files finish downloading and parsing.

Fix:

  • Move non-critical JavaScript to the bottom of the page or use defer / async attributes
  • Inline critical CSS (the styles needed to render the above-the-fold content) directly in the HTML
  • Remove any CSS or JS you're no longer using

7. Too Many Plugins (WordPress)

Each active WordPress plugin adds code that runs on every page load. A site with 30+ plugins — especially ones with poorly written queries — can be significantly slower than the same site with a lean set of well-maintained plugins.

Fix: Audit your plugins. Deactivate and delete anything you don't actively use. Replace multiple single-purpose plugins with a well-built all-in-one alternative where possible.

8. Unoptimised Database

On database-driven sites, slow or unindexed queries add time to every page load. Databases that have never been cleaned up can also accumulate bloat over time.

Fix:

  • Add indexes to columns used in frequent WHERE clauses
  • Use EXPLAIN to analyse slow queries and identify missing indexes
  • For WordPress: periodically clean up post revisions, transients, and spam comments

9. Shared Hosting at Capacity

On shared hosting, you share server resources with other websites. When other sites on the same server spike in traffic or run heavy processes, your site slows down too — you have no control over it.

If you're on shared hosting and have outgrown it, moving to a VPS gives you dedicated resources and much more predictable performance.

How to Measure Your Page Speed

Before optimising, measure. Free tools:

Run tests from multiple locations to understand the geographic component of your performance.

Speed and Uptime Go Together

Page speed is one dimension of website health — availability is another. A fast site that goes down without anyone noticing is still a broken experience for your visitors.

Domain Monitor monitors your site's availability and response time every minute, alerting you if it goes down or starts slowing significantly. Combine performance optimisation with continuous monitoring for a site that's both fast and reliable.

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