Why your website is slow, and how to fix it.
Google says page speed is part of how it ranks pages, and a slow page gives visitors longer to give up. The causes to look at are images, page builders, plugins, caching, hosting and other people’s scripts. Measure first, then work through them in order.
- Measure on a phone, not a desktop
- Fix the biggest cause first
Measure it properly first.
Put your homepage, and one of your busiest pages, into Google’s PageSpeed Insights (pagespeed.web.dev). Look at the mobile result, not desktop: phones have slower processors and connections, and Google indexes the mobile version of a site.
The page shows two kinds of figures. The top section, when there is enough traffic, is real data from Chrome users who visited your site over the last 28 days. The score below it is a lab test run once from Google’s servers. The real data is what Google uses; the lab test is what helps you find the cause.
Google’s three Core Web Vitals, and the level it calls good:
The three numbers that matter.
| Measure | What it means | Good |
|---|---|---|
| Largest Contentful Paint (LCP) | How long until the main image or heading appears | 2.5 seconds or less |
| Interaction to Next Paint (INP) | How quickly the page responds when someone taps or clicks | 200 milliseconds or less |
| Cumulative Layout Shift (CLS) | How much the page jumps around while it loads | 0.1 or less |
Google measures each one at the 75th percentile: three in four visits need to reach that level for the page to pass.
The causes, and what to do.
Images far bigger than they need to be
A photo straight off a phone can be several megabytes, shown in a space a few hundred pixels wide. Resize images before uploading, serve them in WebP or AVIF, and let everything below the first screen load as the visitor scrolls.
A page builder
Builders such as Elementor and Divi add their own code and styles to the pages they build, much of it unused. Settings can trim some of it; removing it means rebuilding the pages.
Plugins that load on every page
What each plugin adds to the page counts for more than how many there are. Sliders, form plugins and social feeds can load their scripts on every page, even where they are not used. Remove what is unused and check what the rest load.
No caching, or caching that isn’t working
Without a cache, WordPress builds every page from the database for every visitor. A caching plugin, or Cloudflare with a rule to cache pages, serves a saved copy instead. Check it is actually working: a misconfigured cache can be switched on and still do nothing.
Slow hosting
If the server takes a long time to send the first byte of the page, nothing else can start. PageSpeed Insights reports this under Document request latency. Caching only partly hides a slow server.
Other people’s scripts
Chat widgets, ads, embedded maps, booking widgets and tracking tags all load code from elsewhere that you cannot speed up. Load them only where they are needed, or behind a click: a map can be an image until someone taps it.
A real example: FMTweak.
FMTweak, a Football Manager mods site, had several of these at once: a page builder, dozens of plugins, and pages Cloudflare was not set up to cache. It was rebuilt without a page builder. With the old plugins still installed, an article page then scored 70 on mobile PageSpeed, with a Largest Contentful Paint of 6.2 seconds. Removing the old plugins and caching pages at Cloudflare took it to 91, and the Largest Contentful Paint to 2.1 seconds.
It also shows the limit of what a site owner controls. FMTweak runs display ads, and the ad network’s scripts add about 400 KB of code to each page, outside our control. Read the case study for the full before and after.
Which order to fix it in.
Start with what PageSpeed Insights lists under Insights, which shows the estimated saving for each fix. A typical order:
- Compress and resize the largest images, starting with whatever is at the top of the homepage.
- Check caching is working, and add Cloudflare, with page caching switched on, if the site has no CDN.
- Remove unused plugins, then look at what the remaining ones load.
- Move maps, videos and chat widgets behind a click.
- Measure again. If server response time is still slow, look at the hosting.
If the page builder is the main cost, the choice is between living with it and rebuilding without one. That is a bigger job, so it is worth doing the cheaper fixes first and measuring what is left.
Website speed questions
Ask us something else →Why does my site feel fast to me but score badly?
Your browser has cached it, and you may be on a fast connection and a desktop. PageSpeed Insights simulates a first visit on a mid-range phone over a throttled mobile connection.
Does speed really affect Google rankings?
Google says its ranking systems use Core Web Vitals as part of page experience, alongside many other signals, with the content of the page first among them.
Will a caching plugin fix everything?
It helps with server response time, which is one cause. It does not shrink images, remove page builder code or speed up third-party scripts.
Can you check my site?
Yes. The free website check looks at speed on phones and tells you which of these causes applies.
We can fix it for you.
Send us your website address. We will tell you what is slowing it down and what it would take to fix, whether that is a clean-up or a rebuild.
Get a free website check →