IPv6 Address Tool
Expand, compress, and identify any IPv6 address type
Address type
Global Unicast
2000::/3 — publicly routable, equivalent to public IPv4 addresses
128-bit group breakdown (8 × 16-bit groups)
IPv6 address type reference
Frequently asked questions
How do you compress an IPv6 address?
Two rules apply: (1) Leading zeros in each group can be dropped — 0001 becomes 1. (2) One consecutive run of all-zero groups can be replaced with :: — but only once per address. Example: 2001:0DB8:0000:0000:0000:0000:0000:0001 → 2001:db8::1.
What is a link-local IPv6 address?
Link-local addresses start with FE80::/10 (FE80 through FEBF). They are automatically assigned to every IPv6-enabled interface and are used for communication on the local link only — they cannot be routed beyond the local network segment.
What is the IPv6 loopback address?
The IPv6 loopback address is ::1 (fully expanded: 0000:0000:0000:0000:0000:0000:0000:0001). It is equivalent to 127.0.0.1 in IPv4 and is used for local testing.
What prefix is used for global unicast addresses?
Global unicast addresses use the 2000::/3 prefix — meaning addresses starting with binary 001. In practice, the IANA has allocated 2000::/3 which covers addresses from 2000:: to 3FFF:FFFF:... These are the publicly routable IPv6 addresses.
How long is an IPv6 address?
IPv6 addresses are 128 bits long, written as 8 groups of 4 hexadecimal digits separated by colons (e.g., 2001:0db8:0000:0000:0000:0000:0000:0001). Compared to IPv4's 32 bits, IPv6 provides approximately 3.4 × 10³⁸ possible addresses.