IPv6 subnet calculator

IPv6 CIDR range for fec0::/125

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 fec0::/125

The prefix identifies a network with 3 host bits. Every address from the first address through the last address belongs to this range.

CIDR prefix

fec0::/125

Network mask

ffff:ffff:ffff:ffff:ffff:ffff:ffff:fff8

Prefix length

/125

Host bits

3

First address

fec0::

Last address

fec0::7

Total addresses

8

Total addresses (human readable)

2^3 addresses (8)

How this range is calculated

  1. 1The /125 prefix keeps the first 125 network bits fixed.
  2. 2Setting all 3 host bits to zero produces fec0::.
  3. 3Setting those host bits to one produces fec0::7.

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

fec0:0000:0000:0000:0000:0000:0000:0000

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