IPv6 tools

Paste an IPv6 address to see its fully expanded and canonically compressed forms, and add a /prefix to get the network address and number of addresses.

Paste an IPv6 address to see its fully expanded and canonically compressed forms, and add a /prefix to get the network address and number of addresses.

How to use

  1. Type an IPv6 address like 2001:db8::1
  2. Read the expanded and compressed (RFC 5952) forms
  3. Add a prefix such as /32 to compute the subnet
  4. Click a value to copy it

Frequently asked questions

What does compression do?

It applies RFC 5952: drops leading zeros and collapses the longest run of zero groups into ::, giving the canonical short form.

How large can a subnet be?

IPv6 uses 128-bit addresses, so counts are computed with big-integer math — a /64 holds 2^64 addresses.

Is :: allowed more than once?

No. A valid address has at most one :: ; inputs with two or with ::: are rejected.