IPv6 Expander and Compressor

How to use

1. 1Paste any IPv6 address into the input. Compressed (::), expanded (full 8 groups), embedded IPv4 (::ffff:192.0.2.1), bracketed ([2001:db8::1]), zone-tagged (fe80::1%eth0), and prefix-suffixed (2001:db8::/32) forms are all accepted.
2. 2Read the Address forms card to see the expanded full form, the no-leading-zeros form, the RFC 5952 compressed form, the 32-character no-colon hex, the embedded IPv4 view when applicable, and the reverse-DNS (ip6.arpa) PTR name.
3. 3Check the Address type panel for classification, including loopback, link-local, unique local, multicast (with scope), IPv4-mapped, 6to4, documentation, Teredo, or global unicast.
4. 4Add a /prefix at the end of the address (for example 2001:db8::/32 or fd00::1/48) to see the network address and the total number of addresses inside the prefix.
5. 5Use the Copy button on any field to grab the result, or click a Quick sample to load common patterns like loopback (::1), unspecified (::), or link-local (fe80::1ff:fe23:4567:890a%eth0).

About this tool

IPv6 Expander and Compressor turns any IPv6 address into every representation you might need for documentation, network configuration, debugging, or reverse DNS work. Paste an address in any common form: compressed with :: like 2001:db8::1, fully expanded like 2001:0db8:0000:0000:0000:0000:0000:0001, with an embedded IPv4 like ::ffff:192.0.2.1, with a zone identifier like fe80::1%eth0, with surrounding brackets like [2001:db8::1], or with a CIDR prefix like 2001:db8::/32. The tool validates the input strictly, points to the exact group that fails parsing when something is wrong, and then derives the full set of forms in parallel: the expanded eight groups with every group padded to four hex digits, the same address with leading zeros stripped, the canonical RFC 5952 compressed form (lowercase hex, leftmost longest zero run replaced with ::, single zero groups left alone), a 32-character no-colon hex string, the binary breakdown of all 128 bits in eight 16-bit groups, the decimal value computed with BigInt for use as a stable integer key, the reverse-DNS PTR name under ip6.arpa with one nibble per label, and an automatic IPv4-mapped view when the last 32 bits look like a dotted-decimal address. The address type panel classifies the prefix using RFC 4291 and related registries: loopback, unspecified, link-local (fe80::/10), unique local (fc00::/7), multicast (ff00::/8 with the resolved scope), IPv4-mapped (::ffff:0:0/96), 6to4 (2002::/16), documentation (2001:db8::/32), Teredo (2001::/32), and global unicast (2000::/3). When a CIDR prefix is provided the tool also clears host bits to show the network address in both compressed and expanded forms and reports the total address count inside the prefix as a 2^N value. Everything runs locally with bitwise math and BigInt, so no address you paste here is uploaded, logged, or stored. Useful for IPv6 PTR record creation, dual-stack documentation, firewall rule normalization, reading packet captures, verifying configuration files, and any time you need to convert between the compressed and full forms with confidence.

Free to use. Works in your browser. No signup, no login.