There are various addressing schemes on the internet - IPv4 and the new, still not very well adopted IPv6, MAC addresses, etc. I wonder how the number of each of these fares when stacked up against the world's population of ~7 billion people.

IPv4 Addresses

An IPv4 address consists of 4 numbers, each between 0 and 256, separated by dots (e.g. 52.11.108.247). The theoretical maximum number of addresses is therefore 256 to the 4th power:

256⁴ = 256 x 256 x 256 x 256 = 4,294,967,296

If we divide this by our 7 billion people, we get:

4,294,967,296 / 7,000,000,000 = 0.61

This is 0.61 IP addresses per person, or an IP address per 0.61 / 1 = 1.63 people.

Eek, that doesn't seem to be enough! Remember that every home has a public IP, and each internet connected mobile device (mobile phones, etc) also has a public IP.

IPv6 Addresses

IPv6 was created to help alleviate the issue of a lack of IPv4 addresses. An IPv6 address consists of 6 groups of two hexadecimal (0-9 or a-f) digits, separated by colons (e.g. 16:a2:aa:73:60:4b). The theoretical maximum number of addresses is therefore 16 to the 16th power:

16¹⁶ = 16 x 16 x 16 x 16 x 16 x 16 x 16 x 16 x 16 x 16 x 16 x 16 x 16 x 16 x 16 x 16 = 18,446,744,073,709,600,000

If we divide this by our 7 billion people, we get:

18,446,744,073,709,600,000 / 7,000,000,000 = 2,635,249,153

This is around 2.6 billion addresses per person - much better! It's interesting that IPv5 doesn't really seem to have taken off as an alternative to IPv4 as of yet - a lot of infrastructure supports IPv6, but wherever public IPv6 addresses are given out it's alongside an IPv4 address.

MAC Addresses

MAC addresses are used for both Ethernet and Bluetooth, and are unique IDs allotted to all network communication devices (e.g. network cards, wireless devices), and consist of 6 pairs of hexadecimal characters, separated by colons (e.g. 05:AB:F5:20:94:9C). The theoretical maximum number of addresses is therefore 16 to the 12th power:

16¹² = 16 x 16 x 16 x 16 x 16 x 16 x 16 x 16 x 16 x 16 x 16 x 16 = 281,474,976,710,656

If we divide this by our 7 billion people, we get:

281,474,976,710,656 / 7,000,000,000 = 40,211

This is about 40 thousand addresses per person - which seems acceptable.