/8 Subnet: Mask 255.0.0.0, 16,777,214 Usable Hosts

A /8 subnet has a subnet mask of 255.0.0.0 and contains 16,777,216 total IP addresses, of which 16,777,214 are usable host addresses (the network and broadcast addresses are reserved). A /8 contains 65,536 /24 networks.

Usable hosts in a /8 by platform

Cloud providers reserve more than the usual two addresses per subnet, so the same /8 gives you fewer usable IPs in the cloud than on a standard LAN.

Good to know

A /8 is a former "Class A" network with over 16 million addresses. The 10.0.0.0/8 private range is the most famous example, giving home labs and enterprises a huge private space.

How a /8 is calculated

• The /8 means the first 8 bits are the network portion, leaving 24 host bits.
• Total addresses = 2^(32 - 8) = 2^24 = 16,777,216.
• Usable hosts (standard) = 16,777,216 - 2 (network + broadcast) = 16,777,214.
• Subnet mask = 255.0.0.0; wildcard mask = 0.255.255.255.