CIDR prefix
/23
255.255.254.0
510 usable hosts · 512 addresses
The mask for /23 is 255.255.254.0 — 512 addresses, 510 usable hosts. Campus and larger office networks; /22–/23 are common for offices with a few hundred devices.
Mask
255.255.254.0
Wildcard
0.0.1.255
Addresses
512
Hosts
510
Worked example: 192.168.0.0/23
Network address192.168.0.0/23
Broadcast address192.168.1.255
First host192.168.0.1
Last host192.168.1.254
FAQ — /23
What is the subnet mask for /23?
The subnet mask for /23 is 255.255.254.0 (wildcard: 0.0.1.255). The first 23 bits are the network part, the remaining 9 are the host part.
How many hosts fit in a /23?
A /23 block holds 512 addresses, of which 510 are usable hosts (the network and broadcast addresses are excluded).
How many /23 subnets fit in a /16?
A /16 network divides into 128 /23 subnets.
What is a /23 used for?
Campus and larger office networks; /22–/23 are common for offices with a few hundred devices.