Slow website on mobile: a Lighthouse test of 78 company websites in Harghita, with a 13-second median LCP

The fourth part of the Harghita website study is about mobile speed: a Lighthouse test of 78 company homepages, the time until the largest content element appears (LCP) and page weight. It shows what slows most sites down, and what does not.

Lassú weboldal mobilon: 78 hargitai céges oldal Lighthouse-mérése, 13 másodperces medián LCP

In short: The 78 Harghita company homepages I tested have a median mobile Lighthouse score of 57.5, and only 3 reached 90. On simulated slow 4G the median LCP is 13.3 seconds, the median homepage weighs 4.1 MB, and 35 sites are heavier than 5 MB.

A slow website on mobile costs you more than patience: Google looks at the mobile version first, and visitors do not wait. In the fourth part of the series on the websites of 100 companies in Harghita County, I measured the mobile speed of 78 company homepages with Google Lighthouse.

How I measured

The measurement was taken on 27 September 2026. The sample: the 50 largest companies in Harghita County from the Termene 2025 revenue ranking, and 50 small businesses from different sectors. Of the 81 working websites, Lighthouse ran without errors on 78, and the numbers refer to these. On each site I tested the homepage with the default Lighthouse mobile profile, once, while no other measurement was running on the machine.

Limits: this is a lab test on simulated slow 4G with a throttled processor, and does not reflect real user data. On a good mobile connection every site is faster than what I measured here, but the ranking of the sites relative to each other stays similar. There is some variation between runs, so I report medians rather than individual values. The small-business half contains only companies with a working website. For reference: my own website scored 95 with the same tool.

The result: a median of 57.5 points

  • Median: 57.5 points out of 100.
  • 90 or above (green): 3 websites of 78 (4%).
  • Between 50 and 89 (orange): 56 websites.
  • Below 50 (red): 19 websites (24%).

There is little difference between large companies and small businesses: the medians are 56 and 58 points. WordPress does not explain it either: WordPress sites have a median of 56.5, the others 58.

LCP: 13 seconds until the main content appears

More important than the score is LCP (Largest Contentful Paint): how long it takes for the largest content element, usually the main image or the headline, to appear on screen. According to Google's web.dev guidance, under 2.5 seconds is good and over 4 seconds is poor.

  • The median LCP is 13.3 seconds.
  • On 70 of 78 websites (90%) it is over 4 seconds.
  • Only 3 websites stay under 2.5 seconds.
  • The slowest quarter is above 21.4 seconds, and on 23 websites LCP is over 20 seconds.

For comparison: on my own fast internet connection, without throttling, the median homepage loaded in about 1.6 seconds. So on a desktop many sites seem fine; the problem appears on mobile with a weaker signal, which is where part of the visitors actually browse.

Slow website on mobile: page weight is the main cause

If the platform does not make the difference, what does? According to the measurement, mostly page weight:

  • The median homepage weighs 4.1 MB.
  • 35 websites (45%) are heavier than 5 MB, 10 are heavier than 10 MB, and the heaviest is 42 MB.
  • Pages of at most 2 MB (21 websites) have a median score of 66, pages over 5 MB (35 websites) only 55.
  • The homepages of large companies weigh 6.4 MB at the median, those of small businesses 3.3 MB.

JavaScript blocking time (TBT), on the other hand, is not an outlier on most sites: the median is 90 milliseconds. So what slows the typical Harghita company website down is mainly the amount of content it downloads, more than the code. I did not break down exactly what on each site, but in my experience it is most often oversized images, a header video and fonts loaded for no reason. Layout shift (CLS) exceeds the good threshold of 0.1 on 13 websites.

A 4 MB homepage on mobile data is slow and also eats into the visitor's data plan. And a 42 MB page on simulated slow 4G is practically impossible to wait out.

What can you do?

Most websites can be sped up without a rebuild:

  • Resize and compress your images (WebP, cut to their display size). On a 5 MB page this is often most of the weight.
  • Replace the header video with a still image on mobile.
  • Load only the fonts and weights you actually use.
  • Measure your own site on pagespeed.web.dev, on mobile, and look at LCP as well as the score.

I described the detailed steps in the article on a faster WordPress site, and what I did differently on my own website in the PageSpeed case study. The earlier parts of this series cover legal compliance and HTTPS and security.

If you are curious where your website stands, send me its address: I will measure it with the same tool and tell you what is slowing it down.

Sárosi Zoltán

Written by

Sárosi Zoltán

Founder, WordPress developer – Eagle Solutions

I have been building websites and online stores from Harghita County since 2011, for small businesses, associations and agency partners. Everything I write here comes from my own projects.

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