Learn to calculate subnet boundaries and usable host ranges with practical examples.
Subnet identifier.
Targets all hosts in subnet.
Assignable IP addresses.
Except special /31 and /32 cases
Steps to calculate a subnet
Convert IP and mask to binary, apply AND for network, then set host bits to 1 for broadcast.
Once both boundaries are known, usable range is the space in between.
Quick /24 example
IP 192.168.1.34/24 -> network 192.168.1.0 and broadcast 192.168.1.255.
Usable hosts: 192.168.1.1 to 192.168.1.254.
Special /31 and /32 cases
In /31, point-to-point links often use both addresses, so classic network/broadcast reservation differs from regular subnets.
In /32, the address identifies a single host route.
Understanding these edge cases prevents routing and addressing mistakes.
Quick validation checklist
Verify IP belongs to subnet range and prefix matches the decimal mask shown.
Ensure network and broadcast addresses are not assigned to endpoints.
A subnet calculator helps reduce repeated manual errors.
Frequently asked questions
Can network/broadcast be assigned?
No, both are reserved.
How many hosts in /27?
30 usable hosts.
How many usable hosts in /26?
62 usable hosts.
What is a broadcast address?
It is the last subnet address used to reach all hosts in that segment.
How can I avoid host range mistakes?
Find network and broadcast first, then use the addresses in between.
