IPv6 subnet calculator

IPv6 CIDR range for ::/31

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 ::/31

The prefix identifies a network with 97 host bits. Every address from the first address through the last address belongs to this range.

CIDR prefix

::/31

Network mask

ffff:fffe::

Prefix length

/31

Host bits

97

First address

::

Last address

0:1:ffff:ffff:ffff:ffff:ffff:ffff

Total addresses

158456325028528675187087900672

Total addresses (human readable)

2^97 addresses (158,456,325,028,528,675,187,087,900,672; about 158.45 octillion)

How this range is calculated

  1. 1The /31 prefix keeps the first 31 network bits fixed.
  2. 2Setting all 97 host bits to zero produces ::.
  3. 3Setting those host bits to one produces 0:1: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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