IPv6 subnet calculator

IPv6 CIDR range for ::/2

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 ::/2

The prefix identifies a network with 126 host bits. Every address from the first address through the last address belongs to this range.

CIDR prefix

::/2

Network mask

c000::

Prefix length

/2

Host bits

126

First address

::

Last address

3fff:ffff:ffff:ffff:ffff:ffff:ffff:ffff

Total addresses

85070591730234615865843651857942052864

Total addresses (human readable)

2^126 addresses (85,070,591,730,234,615,865,843,651,857,942,052,864; about 85.07 undecillion)

How this range is calculated

  1. 1The /2 prefix keeps the first 2 network bits fixed.
  2. 2Setting all 126 host bits to zero produces ::.
  3. 3Setting those host bits to one produces 3fff:ffff:ffff: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

0000:0000:0000:0000:0000:0000:0000:0000

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