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Calixo

IPv6 Address Calculator

Expand a shorthand IPv6 address to its full form, or compress it to canonical shorthand.

Inputs

Saved Scenarios

— select 2+ to compare

Expanded (Full) Form

2001:0db8:0000:0000:0000:8a2e:0370:7334

Compressed (Canonical) Form

2001:db8::8a2e:370:7334

Spark says

Formula

Compressed=Collapse the longest run of zero groups to "::"Compressed = Collapse\ the\ longest\ run\ of\ zero\ groups\ to\ "::"
::
— Shorthand for one or more consecutive all-zero 16-bit groups

What is the IPv6 Address Calculator?

IPv6 addresses are 128 bits, written as eight 16-bit hex groups — the '::' shorthand collapses one run of consecutive zero groups for readability. This calculator converts between the full and compressed forms.

How to use it

  1. 1 Enter an IPv6 address, in either full or shorthand ('::') form.

Worked examples

2001:db8::8a2e:370:7334

Expands to 2001:0db8:0000:0000:0000:8a2e:0370:7334.

Try it

Limitations

  • •Handles standard IPv6 notation only — doesn't currently parse embedded IPv4-mapped addresses (e.g. ::ffff:192.0.2.1) or zone/scope IDs (%eth0).

Frequently asked questions

Why can only one '::' appear in an address?

If two '::' were allowed, the number of zero groups each represents would be ambiguous — the standard restricts every address to at most one '::' for exactly this reason.