Subnet and CIDR calculator
Normalize a prefix, inspect its address boundaries and copy the result. Calculating a block does not perform an IP lookup.
::/128
Normalized IPv6 network
128 network bits0 host bits
- First address
- ::
- Last address
- ::
- Total addresses
- 1
- Prefix length
- /128
IPv6 prefix details
- Network bits
- 128
- Address bits after the prefix
- 0
IPv6 has no broadcast address. Address-space counts do not measure assigned devices or available interface identifiers.
No published network profile is available for this exact CIDR. The boundary calculation is still valid.
Reading the calculation
The prefix fixes the network bits. The remaining n bits give 2^n addresses. This is the size of the block, not an allocation, announced route or count of active devices.
IPv4 /31 point-to-point links use both addresses; a /32 identifies one address. IPv6 has no broadcast address. Documentation blocks such as 192.0.2.0/24 and 2001:db8::/32 do not imply public routability.