Your website is slow: 5 causes and what to do about them

A visitor decides within a few seconds whether to stay. If your website loads slowly, especially on a phone, part of your visitors leave before they have read a single sentence. And Google also takes into account how fast and stable your pages load.

The good news: a slow website almost always has a handful of recognisable causes. Below are the five we come across most often.

First: measure how slow your site really is

Go to Google’s PageSpeed Insights, enter your address and look at the result for mobile. Three numbers matter:

• LCP: how quickly the largest element (usually your big photo or headline) is visible. Good is within 2.5 seconds.
• INP: how quickly your page responds when someone taps something. Good is under 200 milliseconds.
• CLS: how much the page jumps around while loading. Good is under 0.1.

Do not measure just once but a few times, and test a few important pages besides your homepage.

1. Images that are too heavy

This is by far the most common cause. A photo from your phone is easily 4 to 6 MB and often 4000 pixels wide, while your website only shows it 1200 pixels wide. Resize photos before you upload them, use a modern format such as WebP, and let images lower on the page load only when the visitor scrolls to them.

2. Too many plugins and scripts

A chat window, a slider, a pop-up, three tracking codes, an Instagram feed: every part loads extra files. On its own it seems small, together it slows your site down considerably. Go through your plugins and ask yourself for each one: do we still use this, and does it bring anything?

3. Cheap or outdated hosting

Is your site on an overcrowded server, or does it still run on an old PHP version? Then the rest can be as good as it gets, the server simply responds slowly. In PageSpeed Insights, look at the server response time. If it is consistently high, the problem is your hosting.

4. No caching

Without caching your website builds every page from scratch for every visitor. With caching a ready-made version is stored and shown straight away. That is often the biggest gain for the least effort, as long as it is set up properly, so your contact form and shopping cart keep working.

5. Fonts and external content

Fonts from an external service, an embedded YouTube video or a Google Maps map at the top of your page: they all come from another server and make your page wait. Host fonts yourself, use no more than you need, and let videos and maps load only when someone clicks them.

What does it bring?

A fast site feels more professional, visitors view more pages and leave less quickly. Speed is also one of the signals Google uses. It will not turn a weak page into a winner, but between two similar pages it can make the difference.

Need help?

Want to know why your site is slow and what gains the most? Take a look at our speed optimisation, or send us your address. We will tell you honestly where the gains are.