IPv6 subnet calculator

IPv6 CIDR range for fddd::/23

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 fddd::/23

The prefix identifies a network with 105 host bits. Every address from the first address through the last address belongs to this range.

CIDR prefix

fddd::/23

Network mask

ffff:fe00::

Prefix length

/23

Host bits

105

First address

fddd::

Last address

fddd:1ff:ffff:ffff:ffff:ffff:ffff:ffff

Total addresses

40564819207303340847894502572032

Total addresses (human readable)

2^105 addresses (40,564,819,207,303,340,847,894,502,572,032; about 40.56 nonillion)

How this range is calculated

  1. 1The /23 prefix keeps the first 23 network bits fixed.
  2. 2Setting all 105 host bits to zero produces fddd::.
  3. 3Setting those host bits to one produces fddd:1ff: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

fddd:0000:0000:0000:0000:0000:0000:0000

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