IPv6 subnet calculator

IPv6 CIDR range for 2001:ef01:2345::fff0/124

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:ef01:2345::fff0/124

The prefix identifies a network with 4 host bits. Every address from the first address through the last address belongs to this range.

CIDR prefix

2001:ef01:2345::fff0/124

Network mask

ffff:ffff:ffff:ffff:ffff:ffff:ffff:fff0

Prefix length

/124

Host bits

4

First address

2001:ef01:2345::fff0

Last address

2001:ef01:2345::ffff

Total addresses

16

Total addresses (human readable)

2^4 addresses (16)

How this range is calculated

  1. 1The /124 prefix keeps the first 124 network bits fixed.
  2. 2Setting all 4 host bits to zero produces 2001:ef01:2345::fff0.
  3. 3Setting those host bits to one produces 2001:ef01:2345::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:ef01:2345:0000:0000:0000:0000:fff0

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