I tested WordPress agency website speed the way a visitor on a phone would meet it. The question was simple: if agencies sell speed and care to their clients, how fast are their own home pages? I ran 26 of them through Lighthouse on mobile and kept the numbers. The short answer is that most were slower than I expected, and the problem was rarely layout shift. It was how long the main content took to appear and how much each page weighed.
This is a small test, and I explain its limits below before you read anything into it.
What did I measure, and how?
I collected 32 agency home pages through searches for WordPress and web design agencies in cities across the US, UK, Canada and Australia. Six showed no sign of WordPress and were left out, which left 26. For each one I ran Lighthouse 12.8.2 three times with its default mobile settings, which simulate a mid-range phone on a slow 4G connection, and kept the median run. All runs were done on 29 October 2026 from my own machine.
I’m not naming any agency. The point is the pattern, not who landed where.
What were the results?
| Measure | Result across 26 sites |
|---|---|
| Median mobile performance score | 56.5 out of 100 (middle half between 43 and 83) |
| Scored 90 or higher | 3 of 26 |
| Scored below 50 | 8 of 26 |
| Median Largest Contentful Paint (LCP) | 7.6 seconds |
| LCP at or under 2.5 seconds | 1 of 26 |
| LCP above 4 seconds | 18 of 26 |
| Total blocking time at or under 200 ms | 10 of 26 |
| Layout shift (CLS) at or under 0.1 | 23 of 26 |
| Median page weight | 1.5 MB |
| Pages above 2 MB | 11 of 26 (the heaviest was 28.6 MB) |
What does the pattern say?
Layout shift is mostly handled. 23 of 26 sites passed it, which suggests current themes and page builders reserve space for images well enough.
Loading the main content is where it falls apart. Google treats an LCP of 2.5 seconds or less as good. LCP measures when the biggest visible element, usually a hero image or headline block, finishes loading. Only one site hit that mark in this lab test, and 18 took longer than 4 seconds.
Heavy pages explain part of it. Eleven pages were above 2 MB, and a phone on a slow connection has to download all of that before the page feels ready. I didn’t open each site to find the cause, so I can’t tell you which pages were slowed by images, scripts, fonts or hosting. Those are the usual suspects, and my guide on why a WordPress site is slow covers how to check each one.
What are the limits of this test?
Please read these before quoting any number:
- Small, searched sample. 26 sites found through city searches lean toward agencies that already rank for local terms. This is not a survey of all WordPress agencies.
- Lab data, not real visitors. Lighthouse simulates one kind of phone and connection. Real visitors on faster devices or networks can see better results, and field data from real Chrome users is the more important measure. My guide to WordPress Core Web Vitals explains the difference.
- One page per site. I tested the home page only. Inner pages can be faster or slower.
- My machine and my network. Scores can shift a few points between runs. The three-run median reduces this but doesn’t remove it.
What should an agency do with this?
Test your own home page the same way before a client does. Open PageSpeed Insights, or run Lighthouse in Chrome DevTools, choose mobile, and look at LCP and page weight first. Then check three things in order:
- The hero image. Is it sized for a phone, in a modern format, and loaded first rather than lazy-loaded?
- Scripts and plugins loading on every page. Sliders, chat widgets, tag managers and unused plugins add weight everywhere.
- Hosting and caching. A slow first response delays everything after it. Make sure there is one working cache, not three.
Can I get my own site or my clients’ sites checked?
If you’re an agency, send me your home page for a free check and I’ll run the same test and tell you what I’d fix first. Fixes start from $150 on my WordPress speed optimization page, with before and after numbers measured the same way. If you’d rather not carry speed and upkeep for your clients yourself, see how I work with agencies under their own brand and the white label care plans I run for them.
Common questions
How fast are WordPress agency websites on mobile?
In this small test of 26 agency home pages, the median Lighthouse mobile performance score was 56.5 out of 100, and only 3 sites scored 90 or higher. The median Largest Contentful Paint was 7.6 seconds, against Google's 2.5 second target for a good score.
Is this study representative of all WordPress agencies?
No. The sites were found through city searches, so they lean toward agencies that already rank for local terms. It is a small snapshot, not a survey of the whole market.
Is a Lighthouse score the same as what real visitors experience?
No. Lighthouse simulates a mid-range phone on a slow connection in a lab. Real visitors use many different devices, and Google's field data from real Chrome users can look better or worse. Use Lighthouse to find problems and field data to judge the real picture.
What was the biggest problem on the slow sites?
Late loading of the main content (LCP) and heavy pages. Layout shift was fine on 23 of 26 sites. I did not inspect each site's cause, so treat the usual suspects, large images, heavy scripts and slow hosting, as likely rather than proven.
Written by Sakib Islam, a WordPress developer who builds and looks after sites for businesses and agencies. About my work
