Toolzy

IPv6 Expander & Compressor

Expand a compressed IPv6 address to full form and compress a full one back down.

Expanded form2001:0db8:0000:0000:0000:0000:0000:0001
Compressed form2001:db8::1

Paste any IPv6 address to see both its fully expanded and shortest compressed representations.

How to use

  1. Paste an IPv6 address such as 2001:db8::1.
  2. Read the fully expanded 8-group form.
  3. Read the shortest compressed form.

Frequently asked questions

How does IPv6 compression work?
Leading zeros in each group are dropped and the single longest run of all-zero groups is replaced with :: once.
Why can :: appear only once?
Two :: would be ambiguous because there would be no way to know how many zero groups each one represents.

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