IPv6 Address Expander
Expand and compress IPv6 addresses instantly.
How to use
- 1 Type or paste an IPv6 address, compressed or full.
- 2 Read the fully expanded eight-group form on the left.
- 3 Read the canonical RFC 5952 compressed form on the right.
- 4 Copy whichever representation you need, or inspect the individual groups.
About IPv6 Address Expander
The IPv6 Address Expander converts between the shorthand and the fully written-out forms of an IPv6 address.
Type an address such as 2001:db8::1 and it instantly shows the complete eight-group version, 2001:0db8:0000:0000:0000:0000:0000:0001, with every group padded to four hex digits.
At the same time it gives you the canonical compressed form following RFC 5952 rules — lowercase, no leading zeros, and the longest run of zero groups collapsed to a single "::".
It understands the awkward parts of IPv6 notation that trip people up.
The "::" abbreviation is accepted and validated so it can only appear once and must replace at least one group of zeros.
Addresses with an embedded IPv4 tail, like ::ffff:192.168.0.1, are expanded correctly by folding the dotted-quad into the final two groups.
Surrounding brackets and a trailing zone identifier such as %eth0 are stripped automatically, so you can paste an address straight from a URL or an interface listing.
Each of the eight 16-bit groups is also shown separately for quick reference.
This is useful when configuring firewalls, writing ACLs, comparing addresses that look different but are equal, or simply learning how IPv6 notation works.
All parsing happens locally in your browser with no network calls, so nothing you enter is ever uploaded, and it keeps working offline once loaded.
FAQ
What does "::" mean in an IPv6 address?
It is shorthand for one or more consecutive groups of zeros. It may appear only once in an address, and the expander fills in exactly the right number of zero groups.
Does it support embedded IPv4 addresses?
Yes. A trailing dotted-quad such as ::ffff:192.168.0.1 is converted into the final two 16-bit groups during expansion.
Will it accept brackets or a zone id?
Yes. Surrounding [brackets] and a trailing zone identifier like %eth0 are stripped automatically before the address is parsed.