Convert an IPv4 address to an IPv6 address or an IPv6 address to an IPv4 address.

The IPv4 to IPv6 Conversion Tool

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Our IPv4/IPv6 converter is bidirectional. You can convert IPv4 addresses to IPv6 and you can convert some IPv6 addresses into IPv4. Our converter at this time will only accept IPv4 addresses and IPv4-mapped IPv5 addresses.

Why can't I convert all IPv6 addresses to IPv4?

The reason why you can't convert all of IPv6 addresses to IPv4 is because there are more IPv6 addresses than IPv4 addresses. There are only 340,282,366,920,938,463,463,374,607,431,768,211,456 unique IPv6 addresses, while there are 4,294,967,296 unique IPv4 addresses. These numbers can be calculated based on the address space of each IP version, where IPv4 is 32-bits and IPv6 is 128-bits. From there, the number of unique addresses can be calculated using (2^32) for IPv4 and (2^128) for IPv6. So overall, all IPv4 can be easily converted to IPv6 since the IPv4 address space can live within the IPv6 address space, but a majority of the IPv6 addresses cannot be converted to IPv4, since the IPv4 address space is much smaller than IPv6.

What is IPv4-mapped IPv6 address?

IPv4-mapped IPv6 addresses are IPv6 addresses that represents IPv4 nodes. This can allow them them to be compatible with applications uses AF_INET6 sockets and has IPv6 enabled. A typical IPv4-mapped IPv6 address can look like this ::FFFF:1.2.3.4. This means that the first 80 bits of the address are all 0s, the next 16 bits are FFFF, and the remainder 32 bits are the IPv4 address. Though, we can normalize this address to ::FFFF:102:304, which no longer includes the four-part decimal format in the IPv6 address.