Subnet Calculator
Calculate subnet information including network address, broadcast, and usable hosts
Subnet Calculator Guide
Common Subnet Masks
| CIDR | Subnet Mask | Usable Hosts |
|---|---|---|
| /24 | 255.255.255.0 | 254 |
| /25 | 255.255.255.128 | 126 |
| /26 | 255.255.255.192 | 62 |
| /27 | 255.255.255.224 | 30 |
| /28 | 255.255.255.240 | 14 |
| /29 | 255.255.255.248 | 6 |
| /30 | 255.255.255.252 | 2 |
Key Terms
- Network Address: First IP in the subnet, identifies the network
- Broadcast Address: Last IP in the subnet, sends to all hosts
- Usable Hosts: IPs between network and broadcast addresses
- Wildcard Mask: Inverse of subnet mask, used in routing
Frequently Asked Questions
What is CIDR notation?
CIDR (Classless Inter-Domain Routing) is a method for allocating IP addresses. /24 means the first 24 bits are the network, leaving 8 bits for hosts (256 addresses).
Why are 2 IPs unusable?
The network address and broadcast address are reserved and cannot be assigned to hosts.
What is a /32 subnet?
/32 represents a single IP address with no other hosts in the subnet.
How do I choose the right subnet size?
Choose based on the number of hosts needed. Always plan for growth. Common choices: /24 for small networks (254 hosts), /16 for larger networks.
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