When speaking of IPv6, a question immediately comes up: "How many people do use IPv6 on the Internet?". Answering this question is fundamental to get an immediate understanding of the real adoption of IPv6. A recent overview is presented in RFC 9386.
A count of IPv6 users is monitored by various organizations. For example, both Facebook and Google provide statistics on the users that access their services over IPv6. A very informative blog was posted in 2023 by Cloudflare, showing that humans use IPv6 a lot more than bots, which seem to prefer IPv4. At the end of 2023, Google and Cloudflare roughly agreed on 46% adoption by worldwide users.
Akamai provides data measuring the number of hits to their content delivery platform. For example, they showed 72% adoption in India in early 2024.
APNIC quantifies the use of IPv6 by means of a script that runs on Internet browsers.
Some statistics on DNS records and reachability for top web sites may be found at Dan Wing's site. These data suggest 29% IPv6 penetration by July 2023.
At the time of writing, there are large discrepancies between data from these and other sources. In fact there is no well-defined metric for "how many IPv6 users exist" or "how much IPv6 traffic exists". To take one example, Google estimates the fraction of Google "hits" that use IPv6, yet Google is very little used in China so these data cannot represent the true world-wide situation. Estimates posted to the IETF by Geoff Huston in July 2023 suggest that Google observes a 7% adoption rate in China, while the APNIC measurement reports 30%.
We show here the APNIC presentation of results, as it comes from a Regional Internet Registry (RIR) to show the number of the Internet IPv6 users compared with the total Internet population (in million, see next table).
A third of the Internet population apparently employs IPv6. It is also interesting to look at the growth curve. The main indicator here is the Compound Annual Growth Rate (CAGR), which shows a two-digit growth across the 5-year period 2018-2022.
There is a caveat, though, we may want to consider. The method used by APNIC cannot be fully employed in China, due to local policy filtering traffic from abroad. An independent Chinese research reports 713 million measured IPv6 customers as of September 2022, against the 220 million reported by APNIC. If we add the difference between the two statistics to the global count, we end up with a Ratio of 43.68% in September 2022, not that far from the "psychological" threshold of 50%.