IPv6 Address Converter
Expand or compress IPv6 addresses and identify the type.
🔢IPv6 Address Converter
All processing happens locallyWhat this tool does
IPv6 Address Converter is an IPv6 expander, compressor and address classifier, implements the standard table both ways and locates invalid bytes instead of silently dropping them.
Compression follows RFC 5952: only the longest run of zero groups is collapsed, and it must be at least two groups long, so ::1 and 2001:db8::1 are the canonical forms. Many systems accept non-canonical input; the output here is normalised for comparison.
How to use it
- Paste or type your content into the input field at the top, or press the sample button to load demo data.
- Adjust the options below the input, such as output format, separators, letter case or precision.
- Press the main button to run the conversion. Results appear instantly in the output panel without a page reload.
- When the result looks right, use the copy button in the corner, or download it as a local file.
Tips and notes
Clean up stray spaces and line breaks before pasting for more accurate results.
FAQ
An IPv6 address is 128 bits, and the full 39-character form is hard to read. RFC 5952 defines a single canonical compressed form so each address has one representation.
No. :: means "some number of zero groups omitted here"; allowing it twice would make group positions ambiguous, so the spec permits it once.
A link-local address (fe80::/10) valid only within one segment and never routed. Every network interface generates one automatically.
The bytes are invalid in the chosen encoding — usually the wrong codec.
Yes. The tool is completely free with no usage limits, and you never need an account or a sign-in.
No. All processing runs locally in your browser, so the input never reaches a server and is never logged or stored.
Yes. The layout is mobile-first, so inputs and buttons stay comfortable on phones and tablets in both orientations.
Yes. A copy button in the output panel puts the result on your clipboard, and you can also download it as a text file.