IPv6 subnet calculator

IPv6 CIDR range for fd00::/8

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 fd00::/8

The prefix identifies a network with 120 host bits. Every address from the first address through the last address belongs to this range.

CIDR prefix

fd00::/8

Network mask

ff00::

Prefix length

/8

Host bits

120

First address

fd00::

Last address

fdff:ffff:ffff:ffff:ffff:ffff:ffff:ffff

Total addresses

1329227995784915872903807060280344576

Total addresses (human readable)

2^120 addresses (1,329,227,995,784,915,872,903,807,060,280,344,576; about 1.32 undecillion)

How this range is calculated

  1. 1The /8 prefix keeps the first 8 network bits fixed.
  2. 2Setting all 120 host bits to zero produces fd00::.
  3. 3Setting those host bits to one produces fdff: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

fd00:0000:0000:0000:0000:0000:0000:0000

About this IPv6 prefix

Locally assigned Unique Local Address range: fd00::/8

The fd00::/8 block is commonly used when locally generating Unique Local Addresses for internal IPv6 networks.

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