IPv6 subnet calculator

IPv6 CIDR range for 2001:db8:acad:1::/91

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 2001:db8:acad:1::/91

The prefix identifies a network with 37 host bits. Every address from the first address through the last address belongs to this range.

CIDR prefix

2001:db8:acad:1::/91

Network mask

ffff:ffff:ffff:ffff:ffff:ffe0::

Prefix length

/91

Host bits

37

First address

2001:db8:acad:1::

Last address

2001:db8:acad:1:0:1f:ffff:ffff

Total addresses

137438953472

Total addresses (human readable)

2^37 addresses (137,438,953,472; about 137.43 billion)

How this range is calculated

  1. 1The /91 prefix keeps the first 91 network bits fixed.
  2. 2Setting all 37 host bits to zero produces 2001:db8:acad:1::.
  3. 3Setting those host bits to one produces 2001:db8:acad:1:0:1f: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

2001:0db8:acad:0001:0000:0000:0000:0000

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