CIDR prefix
/8
255.0.0.0
16,777,214 usable hosts · 16,777,216 addresses
The mask for /8 is 255.0.0.0 — 16,777,216 addresses, 16,777,214 usable hosts. A classic Class A block (e.g. 10.0.0.0/8 — the RFC 1918 private range).
Mask
255.0.0.0
Wildcard
0.255.255.255
Addresses
16,777,216
Hosts
16,777,214
Worked example: 10.0.0.0/8
Network address10.0.0.0/8
Broadcast address10.255.255.255
First host10.0.0.1
Last host10.255.255.254
FAQ — /8
What is the subnet mask for /8?
The subnet mask for /8 is 255.0.0.0 (wildcard: 0.255.255.255). The first 8 bits are the network part, the remaining 24 are the host part.
How many hosts fit in a /8?
A /8 block holds 16,777,216 addresses, of which 16,777,214 are usable hosts (the network and broadcast addresses are excluded).
What is a /8 used for?
A classic Class A block (e.g. 10.0.0.0/8 — the RFC 1918 private range).