CIDR prefix
/25
255.255.255.128
126 usable hosts · 128 addresses
The mask for /25 is 255.255.255.128 — 128 addresses, 126 usable hosts. Small office/VLAN segments.
Mask
255.255.255.128
Wildcard
0.0.0.127
Addresses
128
Hosts
126
Worked example: 192.168.0.0/25
Network address192.168.0.0/25
Broadcast address192.168.0.127
First host192.168.0.1
Last host192.168.0.126
FAQ — /25
What is the subnet mask for /25?
The subnet mask for /25 is 255.255.255.128 (wildcard: 0.0.0.127). The first 25 bits are the network part, the remaining 7 are the host part.
How many hosts fit in a /25?
A /25 block holds 128 addresses, of which 126 are usable hosts (the network and broadcast addresses are excluded).
How many /25 subnets fit in a /24?
A /24 network divides into 2 /25 subnets.
What is a /25 used for?
Small office/VLAN segments.