IPv6 subnet calculator

IPv6 CIDR range for 12ff:45f1::/33

Calculate the network address, final address, mask, and exact address capacity of any IPv6 CIDR prefix.

Example: 2606:4700::/32

Host bits are normalized to the network address before the range is calculated.

CIDR calculation

Network details for 12ff:45f1::/33

The prefix identifies a network with 95 host bits. Every address from the first address through the last address belongs to this range.

CIDR prefix

12ff:45f1::/33

Network mask

ffff:ffff:8000::

Prefix length

/33

Host bits

95

First address

12ff:45f1::

Last address

12ff:45f1:7fff:ffff:ffff:ffff:ffff:ffff

Total addresses

39614081257132168796771975168

Total addresses (human readable)

2^95 addresses (39,614,081,257,132,168,796,771,975,168; about 39.61 octillion)

How this range is calculated

  1. 1The /33 prefix keeps the first 33 network bits fixed.
  2. 2Setting all 95 host bits to zero produces 12ff:45f1::.
  3. 3Setting those host bits to one produces 12ff:45f1:7fff:ffff:ffff:ffff:ffff:ffff.

Network address

The normalized prefix base

CIDR notation describes a network, not a single host. If an address with host bits set is entered, this calculator normalizes it to the network base before calculating the range.

Expanded network address

12ff:45f1:0000:0000:0000:0000:0000:0000

Recent network calculations

Recent IPv6 CIDR Ranges

Open recent IPv6 prefixes to inspect their normalized range, mask, and address capacity.

Learn how IPv6 CIDR notation and subnet ranges work