2021 vs 2015 Netflix UK Video Streaming Broadband ISP Speed Index

Once again, we’ve taken our annual look back to see how video streaming speeds via different broadband ISPs have changed for UK users of Netflix’s popular internet movie and TV service. Once again, the top spot continues to be held by Virgin Media (VMO2), but this doesn’t mean what you might think.

Overall, the performance – measured during November of each year – across all the largest UK home broadband providers, has actually decreased a little since 2019 (2020 was skipped because Netflix stopped doing their index due to COVID-19). Indeed, the average speed (Megabits per second) for most providers is now struggling to push above c.3.8Mbps (Megabits per second) – down from the 2019 peak of c.4.5Mbps.

At this point we should highlight that the results for some ISPs have been oddly split by their “DSL” and “Fibre” networks, although it’s unclear whether they mean FTTC (VDSL2), FTTP or both for “Fibre“. Equally, we’re unsure why Netflix has done this for TalkTalk and Sky, but not the other providers, which also have a similarly diverse range of technologies.

One other issue is that Netflix seems to have adopted rounded averages in 2021, which means you can no longer see the subtle differences in performance between ISPs. In the end, Virgin Media topped the table on a speed of 3.8Mbps (down from 4.48Mbps in 2019) and most of the rest produced an identical score of 3.6Mbps.

However, the above results are essentially just a measure of Netflix’s own video streaming performance. Put another way, the index should NEVER be taken as a table that reflects the actual capability of your own home broadband connection, although some other reports have incorrectly explained it like that.

The reason the speeds are so low is because they’re being influenced by a number of key factors, not least the proportion of subscribers who are viewing content in either a low-quality video bitrate like SD (Standard Definition), higher quality HD (High Definition 720p+) or even a 4K (UltraHD) stream.

Crucially, Netflix offers three packages (Basic – £5.99, Standard – £9.99 and Premium – £13.99) and the most popular ones are usually the cheapest two. However, the ‘Basic’ plan only supports SD quality streaming on 1 device, while ‘Standard’ supports HD streaming on 2 devices and ‘Premium’ supports up to 4K streaming on 4 devices. This is important because the transfer speed requirements are influenced by content quality.

Netflix’s Recommended Connection Speeds
* 0.5Mbps – Required broadband connection speed
* 1.5Mbps – Recommended broadband connection speed
* 3.0Mbps – Recommended for SD quality
* 5.0Mbps – Recommended for HD quality
* 25Mbps – Recommended for Ultra HD quality

In other words, the results from each ISP above suggest that the majority of Netflix users are streaming videos in HD and SD, which is reflected in why most of the scores hover just below 4Mbps. But the results can also be impacted by other factors, including video codecs / compression (i.e. bitrates vary as the video stream changes), slow home WiFi, home network congestion and any ISP-side Traffic Management measures etc.

Similarly, ISPs that offer significantly faster speeds are more likely to represent Netflix users with a greater proportion of HD or even 4K accounts, thus it’s no surprise to find that Virgin Media come top of the big boys because their entry-level package is a respectable 50 – 100Mbps.

Over time the rising uptake of faster broadband connections and 4K screens should push the results upwards, but this is often countered by future price hikes that can cause users to downgrade to a lower tier. The results from other countries also tend to be similar to the UK (e.g. South Korea is one of the fastest countries in the world for broadband, but its top ISP is LG U+ at 3.8Mbps).

Ultimately the usefulness of Netflix’s data is questionable and the streaming giant might do better to display extra details, such as by splitting out the difference in performance between SD, HD and 4K streaming, as well as showing the impact at different times of the day (e.g. peak vs off-peak). Sadly, they’ve never provided that information or offered data for smaller ISPs.

This will be the last time we report on Netflix’s speed index as, with connections now getting much faster, it no longer provides any useful context for the wider market.