A slow website costs you customers: anyone staring at a white screen on their phone for more than a few seconds clicks away to a competitor. Fortunately, you can measure how fast your site is yourself in five minutes. In this article you will learn how to do it, how to read the figures and how to tackle the three biggest slowdowns.
Step 1: test your site with PageSpeed Insights
- Go to pagespeed.web.dev (Google’s free testing tool).
- Enter the address of your homepage and click Analyze.
- Look at the Mobile tab first. Most visitors come via their phone, and Google also judges your site on the mobile version.
- Then test your other key pages too, such as a services page, your contact page or a product page. Each page can have different problems.
Step 2: read the results
You get two kinds of information. At the top, if your site has enough visitors, you see real user data: how fast your site was over the past 28 days for visitors using Chrome. Below that is a lab test with a score from 0 to 100. The real data matters most; the lab score is mainly useful for tracking down problems.
Watch these three figures, known as the Core Web Vitals:
| Figure | What it measures | Good |
|---|---|---|
| LCP (Largest Contentful Paint) | How long it takes before the largest element (often the main photo or heading) is visible | 2.5 seconds or less |
| INP (Interaction to Next Paint) | How quickly the page responds when you click or tap something | 200 milliseconds or less |
| CLS (Cumulative Layout Shift) | Whether the page jumps around while loading, so you accidentally click something else | 0.1 or less |
All green? Great. See orange or red? Read on. Don’t panic about a lab score of 60 or 70: plenty of good, busy sites score in that range. What matters more is that the three figures above are in order.
Slowdown 1: images that are too large
This is the biggest culprit on most websites. A photo straight from your phone or camera is easily 4 to 8 MB, while on your site it is shown only a few hundred pixels wide. Here is how to fix it:
- Resize photos before uploading to a maximum of 1920 pixels wide (for a large full-width photo) and smaller for photos within the text.
- Use modern formats such as WebP or AVIF; they are often half the size of JPG at the same quality. Many WordPress plugins convert your images automatically.
- Load photos only when they come into view (lazy loading), except the large photo at the top of the page: that one should load straight away.
In PageSpeed you will recognise this by notices about the delivery, format or size of images, with a list of the photos where you can gain the most.
Slowdown 2: too many plugins and scripts
Every plugin, chat button, slider, social media feed or tracking code loads extra code. A few are no problem; twenty are. Here is how to tackle it:
- Go through your list of plugins in WordPress and ask yourself for each one: do I really still use this?
- Deactivate and delete what you don’t use. Then check that everything still works.
- Replace heavy elements with lighter alternatives, for example a large slider at the top with one good photo and a clear heading. That is often faster and more convincing.
In PageSpeed you will recognise this by notices about unused JavaScript and about files that block the page from being displayed.
Slowdown 3: no caching or a slow server
Without caching, your server builds every page from scratch on every visit. With caching, a ready-made version is stored and served immediately. The server itself also makes a big difference: a cheap package shared by hundreds of sites often responds slowly.
- Check whether you have a caching plugin or whether your host handles caching on the server.
- Look in PageSpeed at the server response time, also called TTFB (time to first byte). If it is consistently above 0.8 seconds, the problem is often the hosting.
- Make sure you run a recent PHP version: newer versions are noticeably faster.
Tip: measure before and after every change, and change one thing at a time. That way you know exactly what the effect was, and you can roll something back if it disappoints. Measuring is knowing.
When should you get help?
Resizing images and cleaning up plugins is something you can easily do yourself. Once it gets more technical, such as a slow server, a heavy theme or an online shop with many products, it is wise to have someone take a look. A wrong setting in a caching plugin can break your site too. With us, this falls under maintenance: we test every change on a copy of your site first and then check that everything works.
Want to know how fast your site really is?
Leave your website address below. We will test your site on mobile and desktop and you will receive a personal report by email: what slows your site down and which three improvements deliver the most. Free and without obligation.
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