IPv6 subnet calculator

IPv6 CIDR range for fd02:1b74:2640::/43

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 fd02:1b74:2640::/43

The prefix identifies a network with 85 host bits. Every address from the first address through the last address belongs to this range.

CIDR prefix

fd02:1b74:2640::/43

Network mask

ffff:ffff:ffe0::

Prefix length

/43

Host bits

85

First address

fd02:1b74:2640::

Last address

fd02:1b74:265f:ffff:ffff:ffff:ffff:ffff

Total addresses

38685626227668133590597632

Total addresses (human readable)

2^85 addresses (38,685,626,227,668,133,590,597,632; about 38.68 septillion)

How this range is calculated

  1. 1The /43 prefix keeps the first 43 network bits fixed.
  2. 2Setting all 85 host bits to zero produces fd02:1b74:2640::.
  3. 3Setting those host bits to one produces fd02:1b74:265f: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

fd02:1b74:2640:0000:0000:0000:0000:0000

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