Convert an IPv6 address into its full 128-bit binary form, group by group, with the prefix boundary marked.
Hexadecimal hides where prefix boundaries fall unless they land on a nibble. Printing all 128 bits makes the split explicit and lets you verify a mask by eye. Non-nibble-aligned prefixes such as /56 or /126 are where IPv6 subnetting mistakes happen, and the binary view is the fastest way to prove a boundary is right.
IPv6 Binary
Each of the eight 16-bit groups is converted to base 2 and padded to 16 digits, giving 128 bits in total.
Each of the eight 16-bit groups is converted to base 2 and padded to 16 digits, giving 128 bits in total. Hexadecimal hides where prefix boundaries fall unless they land on a nibble. Printing all 128 bits makes the split explicit and lets you verify a mask by eye.
Non-nibble-aligned prefixes such as /56 or /126 are where IPv6 subnetting mistakes happen, and the binary view is the fastest way to prove a boundary is right.
This calculator takes 2 inputs: IPv6 address, Prefix length to mark. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.