Top 500 UK Ecommerce Sites – Speed Performance & Core Web Vitals

Last Updated
March 16, 2021

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Here is a table of the top 500 UK retail brands, their Visits per month, Domain Rating, the number of C Class links each has (gathered from Ahrefs), their page speed performance and speed scores, and importantly, their ‘Core Web Vitals’ scores.

The list of 500 is as denoted by Internet Retailing’s “Top 500 Report 2021”, which we would recommend downloading and reading.

Data on site speed was gathered from Reddico‘s free SERP Speed tool, which they’ve kindly provided (They detailed this research in a blog post, but did not include the full list; we thought the full list would be of value).

Core web vitals are, as readers will know, elements from a Google project to prioritise user experience. These are separated into 3 elements:

  • FID = “First Input Delay”, the length of time between a user interacting with an element on a page, and the time when their web browser is able to begin processing in response to that interaction.
  • LCP = “Largest Contentful Paint”, essentially measuring perceived loading speed of a page. In basic terms this is a ‘best guess’ at the point at which a user would perceive the page to have loaded – the point in the timeline of all elements loaded where it is likely the main content has loaded.
  • CLS = “Cumulative Layout Shift”, a measure of elements in pages shifting where the user would likely not expect them to do so (which is often caused by elements loading dynamically within pages).

To those who are not familiar with the above, they may seem very jargonny. An alternate way of thinking about them is FID measures interactivity performance, LCP measures loading performance, CLS measures visual stability.

Together, Google measures these, and publicly announced in late 2020 that they would start using these as part of their algorithms to choose how to rank websites from May 2021.

NB: As you browse down, note that where Speed is ‘0’, results were unavailable at the time. Those have therefore been simply marked ‘Good’ temporarily.

As a recap: The numbers down the left above are each site’s ranking according to the Internet Retailing UK Top 500 Report, which we’d recommend downloading (no affiliation; it is simply useful & interesting).

The data is as of March 2021. As Google begins to fold the three clumsily named ‘Core Web Vitals’ into algorithms affecting their public-facing results in early May, it will be interesting to see whether brands make changes to improve these and, also, whether there are any ranking developments in line with the above.