From a /32 allocation to /48 site prefixes
An allocation such as 2001:db8::/32 contains 2^96 addresses. Splitting it into /48 site blocks uses 16 additional network bits, yielding 2^16 = 65,536 subnets. Each /48 contains 2^80 addresses and can be further divided into 65,536 /64 blocks.
The calculator reports these counts as exact decimal integers and powers of two. Scientific notation is a compact approximation for reading large values; it does not replace the exact decimal result. No floating-point conversion is used for address arithmetic.
Read compressed notation and range boundaries
IPv6 has eight 16-bit hexadecimal groups. Leading zeros may be dropped, and one longest run of two or more zero groups may be written as ::. If runs tie, the leftmost is compressed. For example, 2001:0db8:0000:0000:0000:0000:0000:0001 becomes 2001:db8::1.
The final address of 2001:db8::/32 is 2001:db8:ffff:ffff:ffff:ffff:ffff:ffff. IPv6 has no broadcast address. Counts describe the mathematical size of a block, not a promise that every address is suitable for assignment; protocol and operational reservations still apply.
Why the tool does not list every IPv6 subnet
Even a /64 contains 18,446,744,073,709,551,616 addresses. Generating an address list would be impractical. This tool summarizes normalized notation, boundaries and target capacity, and exports one summary row instead of a massive enumeration.