TL;DR
- On a trade or clinic site, slowness usually comes from full-size photos, a page builder and plugins, chat and tracking scripts, and cheap hosting.
- Test it the way customers use it: on your phone, over 4G, away from the office Wi-Fi.
- Google’s ranking systems use Core Web Vitals from real visitors. The 0–100 PageSpeed score is a lab test for finding problems.
- Start with photos and plugins, which you can usually fix without a developer, then hosting, then code.
- Keep it fast with monthly updates and checks, done by you or a care plan.
Why is my website so slow? On a trade or clinic site, it’s usually a few ordinary problems stacked up. Photos go up straight from a phone at full size, a page builder brings a long list of plugins, a chat widget and tracking scripts load on every page, and the site sits on the cheapest hosting plan. None of them is dramatic. Together they make a page crawl on a phone.
You probably check your site on office Wi-Fi or home broadband, where it looks fine. Your customer opens it on a phone over 4G, on a driveway or in a waiting room. Next time you’re on a job, open your own site with Wi-Fi off and see how long it takes before you can tap your phone number. That’s the version to fix.
Test it the way a customer on 4G sees it
#Three free checks give you the full picture in about ten minutes. Do them on your homepage and your busiest service page, because those are where most visitors land.
- 1
Your phone, with Wi-Fi off
Load both pages over 4G. Note what appears first, and how long it takes before the call button works.
- 2
PageSpeed Insights, mobile tab
Run the same pages through PageSpeed Insights. Its lab test loads the page on a simulated phone over a fixed network and lists what’s slowing it down. Our website grader runs the same mobile test and also checks your titles, indexing and tap-to-call links.
- 3
Search Console’s Core Web Vitals report
Once your site has enough visitors, this shows which pages pass or fail for real users across the whole site. Pages without enough data are left out.
PageSpeed score vs Core Web Vitals: what Google actually uses
#Google’s ranking systems use Core Web Vitals measured from real visitors. The 0–100 PageSpeed score is lab data from one simulated phone on a fixed network, and Google describes lab data as useful for debugging (PageSpeed Insights documentation, 2024). Core Web Vitals come from real visitors, and Google says good Core Web Vitals align with what its core ranking systems seek to reward (Google Search Central, 2025).
So only the field data feeds rankings. The lab score is a diagnostic: it tells you what to fix, and it can move from one run to the next. These are the three field metrics and Google’s targets for each.
- Interaction to Next Paint: the page should respond to a tap in under
- 200 ms
- Google Search Central, 2025
A page passes the Core Web Vitals assessment when the 75th percentile of real visits is good on all three. If your site is too new or too quiet for field data, the reports stay empty and the lab test is all you have, so use it to find problems rather than as a score to chase. Interaction to Next Paint is where most of the technical work lives, and our INP guide covers it in depth.
Why is my website so slow on a phone? The usual culprits
#These are the usual causes on trade and clinic sites. Most slow sites have more than one, which is why fixing a single thing often makes less difference than you’d hoped.
Photos straight from your phone
A photo from a modern phone can be several megabytes. Uploaded as it is into a gallery of recent jobs, one image can outweigh the rest of the page. Resize each photo to the size it’s shown at, save it as WebP, and lazy-load anything below the first screen.
A page builder and a long plugin list
Page builders such as Elementor make editing easy, but they add code to every page, and each plugin can add its own scripts and styles. There’s no safe number of plugins. Ask of each one whether it still earns its place.
Chat widgets, review carousels and tracking scripts
Every third-party script is code from someone else’s server running on your page. A chat widget, a review carousel, a booking pop-up and a couple of tracking tags add up, and they’re a common reason a page is slow to respond when someone taps.
Cheap shared hosting
When the server is slow to respond, everything else waits. Google’s web.dev guidance treats a time to first byte of 0.8 seconds or less as good and more than 1.8 seconds as poor (web.dev, 2025). Compressing photos won’t fix a slow server.
A video or slider as the first thing on the page
A full-width video or rotating slider is usually the largest thing on the first screen, so it sets your Largest Contentful Paint. One well-compressed photo of your own work loads faster and tells customers more.
What to fix first
#Work from quick and cheap to technical. The first stage costs nothing but an afternoon, and re-running PageSpeed Insights after each stage shows you what made the difference.
Tick items off as you go. Re-test on mobile after each stage.
Today
Without a developer
0 of 4 done
Save them as WebP at the width they’re actually shown.
This week
Settings and hosting
0 of 4 done
Check your hosting dashboard. Some hosts include both but leave them switched off.
If it’s regularly slower than web.dev’s 0.8-second guide for time to first byte, talk to your host or move plan.
With a developer
Code and page builders
0 of 4 done
Our INP guide walks through the fixes.
WordPress isn’t slow by default
A WordPress site with decent hosting, a light theme, a short plugin list and compressed photos can be quick. Before you blame the platform or pay for a rebuild, work through the first two stages above.
Keeping it fast after the fix
#Sites slow down again. A new plugin, a gallery of fresh job photos or a new chat widget can undo the work in an afternoon. Put a monthly check in the diary: run your two busiest pages through PageSpeed Insights on mobile, and keep your plugins, theme and software up to date.
If you’d rather hand that over, our care plans do the upkeep. Care, at £25 a month, covers hosting, SSL, backups, updates and 30 minutes of edits. Care+, at £45 a month, adds an hour of edits and a monthly health report. Both are monthly and you can cancel anytime. CodeKodex isn’t VAT-registered, so no VAT is added.
How we help with a slow website
#We start with the free website check, which tests speed on a phone along with four other basics and comes back within 48 hours. If the site needs work, we’ll tell you what and what it would cost.
When a site is slow because of how it was built, patching it can cost more than starting again. Our website redesign service rebuilds it while keeping your URLs and mapping redirects, and every website we build, from £400, is built to load fast on a phone.
Want to know how your site does on a phone?
Our free website check starts with speed on a phone, then looks at your page titles, Google Business Profile, indexing and how easy it is to call or enquire. You get what we’d fix first, back within 48 hours.
Frequently Asked Questions
#Why is my website slow on my phone but fine on my computer?
Your computer is usually on fast broadband with plenty of processing power. A phone on 4G has a slower connection and less power, so heavy photos and scripts hurt far more. Test with Wi-Fi turned off, then run PageSpeed Insights on the mobile setting to see what’s slowing it down.
Does a slow website affect Google rankings?
It can. Google says good Core Web Vitals, measured from real visitors, align with what its ranking systems reward, so a slow site works against you. The PageSpeed score itself isn’t used. Useful, relevant content still matters more, so treat speed as removing a drag rather than a shortcut to the top.
What is a good PageSpeed score?
Lighthouse, which produces the score, colours 90 to 100 green as good and 0 to 49 red as poor. But the score is a lab test for finding problems, and Google doesn’t rank on it. What counts is passing Core Web Vitals for real visitors, so use the score’s list of issues to get there.
Is WordPress slow?
Not by itself. A WordPress site with decent hosting, a light theme, a short plugin list and compressed photos can be quick. It slows down when page builders, plugins and widgets pile up and updates are skipped. If yours is slow, check those before blaming WordPress or paying for a rebuild.
Is my hosting making my website slow?
Check how long your server takes to respond. Google’s web.dev guidance treats a time to first byte of 0.8 seconds or less as good and over 1.8 seconds as poor. If yours is slow even on a simple page, better hosting or caching will help more than compressing another photo.
The short version
#A slow website on a phone usually comes down to heavy photos, plugins and scripts, and cheap hosting. Test it over 4G, fix the photos and plugins first, then the hosting, then the code. Judge your progress on Core Web Vitals from real visitors, and use the lab score to find what to fix next.
Related: visitors but no callsWebsite Getting Traffic but No Enquiries? 7 Things to CheckSpeed is one of seven reasons visitors leave without calling. Here’s how to check the other six.Back to the pillarWhy Websites Fail: 4 Problems That Cost You Leads (and How to Fix Them)Speed is one of four problems behind underperforming websites. The pillar guide covers all of them.Sources
Core Web Vitals and ranking — Google Search Central
Understanding Core Web Vitals and Google search results, updated December 2025
Lab data vs field data — Google for Developers
About PageSpeed Insights, updated October 2024
Core Web Vitals report — Search Console Help
Core Web Vitals report, checked October 2026
Time to first byte — web.dev
Time to First Byte (TTFB), updated November 2025
PageSpeed score colour bands — Chrome for Developers
Lighthouse performance scoring, checked October 2026
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