IPv6 subnet calculator

IPv6 CIDR range for fc00::/7

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 fc00::/7

The prefix identifies a network with 121 host bits. Every address from the first address through the last address belongs to this range.

CIDR prefix

fc00::/7

Network mask

fe00::

Prefix length

/7

Host bits

121

First address

fc00::

Last address

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

Total addresses

2658455991569831745807614120560689152

Total addresses (human readable)

2^121 addresses (2,658,455,991,569,831,745,807,614,120,560,689,152; about 2.65 undecillion)

How this range is calculated

  1. 1The /7 prefix keeps the first 7 network bits fixed.
  2. 2Setting all 121 host bits to zero produces fc00::.
  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

fc00:0000:0000:0000:0000:0000:0000:0000

About this IPv6 prefix

Unique Local Address range: fc00::/7

Unique Local Addresses are intended for private IPv6 networks. They are not globally routed on the public internet.

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