All tools

IPv6 Address Compressor / Expander

Network

Expand an IPv6 address to its full 8-group form or compress it to its RFC 5952 canonical shortest form, and classify its address type

Paste any IPv6 address and see both its full expanded form (all 8 groups, four hex digits each) and its canonical compressed form (RFC 5952: lowercase, no leading zeros, the longest run of zero groups collapsed to a single ::). It also tells you what kind of address it is, loopback, link-local, unique local, multicast, an IPv4-mapped address, a documentation-only address, or an ordinary global unicast address, which is often the detail that actually explains why a connection is or isn't reachable. It understands the two shorthand forms people run into most: a zone/scope ID like %eth0 on a link-local address, and an embedded IPv4 suffix like ::ffff:192.168.1.1. This is address-format inspection only, not a reachability check: it doesn't ping the address or tell you whether it's actually routable from where you're sitting.

ipv6ipnetworkcompressexpandrfc5952

How to use IPv6 Address Compressor / Expander

  • 1.Paste an IPv6 address in any form, compressed or fully expanded, to see both representations side by side.
  • 2.Check the Address Type row to quickly tell a link-local or loopback address apart from a routable global unicast one.
  • 3.Paste an address with a zone ID (like fe80::1%eth0) or an embedded IPv4 suffix (like ::ffff:192.168.1.1) and both are parsed correctly.

Frequently asked questions

Which compressed form does this produce when there's more than one possible way to shorten an address?
It follows RFC 5952: the longest run of consecutive all-zero groups is replaced with ::, and if two runs tie for longest, the leftmost one wins, matching the canonical form most tools and libraries expect.
Does this check whether the address is actually reachable or assigned to anything?
No, it's pure text parsing and classification: it never sends a packet or does a lookup, so a syntactically valid address is not guaranteed to be in use or routable.
What's a zone ID and why does it show up on some addresses?
A zone (or scope) ID like %eth0 disambiguates a link-local address across multiple network interfaces on the same machine; it's kept on both the expanded and compressed output since it's part of how the address is actually used, not a separate field to discard.
Is my input sent anywhere?
No, all parsing happens locally in your browser.

Use via API, SDK, or MCP

cURL# Free: 1,000 req/day · Pro: 10,000 req/day
curl -X POST https://api.utilix.tech/v1/tools/ipv6-compressor \
  -H "Authorization: Bearer utx_live_..." \
  -H "Content-Type: application/json" \
  -d '{"address":"2001:db8::ff00:42:8329"}'

Get an API key from your dashboard · Full API docs →

Related tools

IP/CIDR CalculatorCalculate subnet info, host ranges, and split subnets from CIDR notationNetworkCompress HTMLStrip scripts, styles, comments, classes, and whitespace from HTML to minimize token usage before LLM ingestion.AI / AgentCompress JSONRemove nulls, empty arrays, empty objects from JSON to reduce token footprint before sending to an LLM.AI / Agent