Almost every slow business website is slow for one of four reasons, and they are worth checking in order — because the first one accounts for more than the other three combined and costs nothing to fix.
Measure before you change anything
Run your homepage and one product or service page through PageSpeed Insights. Two numbers matter more than the score.
Time to first byte tells you how long the server took to start responding. If this is over about 600 milliseconds, the server is your floor and nothing you do in the page will get you under it.
Largest Contentful Paint tells you when the main content actually appeared. Under 2.5 seconds is the target.
Also look at total page weight. Anything over about two megabytes for a normal content page is worth investigating on its own.
Cause one: images
This is the answer roughly two times in three.
Someone uploads a photograph straight from a camera or a phone — four thousand pixels wide, four megabytes — and the site displays it at 800 pixels. The browser scales it for display but still downloads every byte first.
Three fixes, in order of effect:
Resize to the size actually used. If the largest it will ever display is 1600 pixels wide, that is the file you should store.
Use modern formats. WebP and AVIF typically cut file size by half or more at the same visual quality.
Load offscreen images lazily. Images below the fold should not compete for bandwidth with the ones the visitor can see.
And declare width and height on every image, which prevents the layout jumping as they load — a separate problem covered in Core Web Vitals explained.
Cause two: the server
If time to first byte is poor, the page has not even started. The usual reasons:
Crowded shared hosting. Budget hosting places hundreds of sites on one machine. When a neighbour has a busy afternoon, you are slow, and there is nothing in your site to fix.
Distance. A UK business hosted in a distant data centre pays a latency penalty on every request. Host near your customers.
Database work on every request. Sites that rebuild every page from scratch, with no caching, do avoidable work for content that has not changed in six months.
Hosting is where businesses most often economise into a problem they then pay a developer to investigate. We cover what to look for in choosing hosting for a UK business.
Cause three: other people's scripts
Open the network tab in your browser's developer tools, reload the page, and look at how many requests go to domains that are not yours.
A typical business site loads: analytics, a tag manager, a chat widget, a cookie banner, a review widget, a font service, a heatmap tool, and two advertising pixels from campaigns that ended last year.
Each is code running on your visitor's phone, fetched from a server you do not control. If one of them is slow, your site is slow, and you have no way to fix it.
The audit is straightforward: list them, ask who uses each one, and remove anything nobody can name a purpose for. This is usually the fastest win after images.
Cause four: plugin and theme bloat
Common on established WordPress sites. Every plugin loads its own scripts and stylesheets on every page whether that page uses the feature or not.
A site with thirty plugins may load a slider library on pages with no slider, a gallery library on pages with no gallery, and three separate icon fonts.
Deactivating what you do not use helps. Beyond a point it becomes an argument for a different approach entirely, which we weigh up in WordPress versus a custom build.
Caching is a good final layer and a poor first fix. It makes a heavy page arrive faster; it does not make it lighter.
Things people fix first that rarely help
Chasing a perfect score. Going from 92 to 98 is developer time spent on something no visitor perceives. Getting from 34 to 80 is worth real money.
Adding a CDN to an already-fast server. Useful for international audiences and image delivery. Not a fix for a bloated page.
Minifying code. Worth doing, but it saves kilobytes while the hero image wastes megabytes.
A realistic order of work
- Fix images across the whole site.
- Check time to first byte and address hosting if it is the constraint.
- Remove third-party scripts nobody uses.
- Remove or replace unused plugins.
- Add caching once the page is actually light.
- Re-measure on a phone on mobile data, not on office broadband.
Following that order, most business websites see the majority of their improvement in the first two steps.
If you would rather have someone measure it properly and tell you where the time goes, our maintenance team does performance diagnostics for UK businesses. Ask us to look at your site.
