Subnet Calculator
Divide networks into subnets, calculate IP ranges, broadcast addresses, and available hosts per subnet. Supports CIDR notation and classful addressing.
Network Input
Subnet Details
Enter a valid IP address to see results
How to Use
- Enter an IP address (e.g.,
192.168.1.0) - Select or enter the CIDR prefix length (e.g.,
/24) - View the calculated network details including usable host range
- Use quick select buttons for common subnet sizes
About Subnetting
Subnetting divides a larger network into smaller, more manageable segments. Each subnet has its own network address, broadcast address, and range of usable host addresses.
CIDR (Classless Inter-Domain Routing) notation uses a prefix length to indicate the subnet mask. For example, /24 means the first 24 bits are the network portion, leaving 8 bits for host addresses (254 usable hosts).
Common Subnet Sizes
| CIDR | Subnet Mask | Total IPs | Usable Hosts | Use Case |
|---|---|---|---|---|
| /8 | 255.0.0.0 | 16,777,216 | 16,777,214 | Large enterprise / Class A |
| /16 | 255.255.0.0 | 65,536 | 65,534 | Medium enterprise / Class B |
| /24 | 255.255.255.0 | 256 | 254 | Small office / Class C |
| /25 | 255.255.255.128 | 128 | 126 | Department / VLAN |
| /26 | 255.255.255.192 | 64 | 62 | Small department |
| /27 | 255.255.255.224 | 32 | 30 | Small workgroup |
| /28 | 255.255.255.240 | 16 | 14 | Small server farm |
| /30 | 255.255.255.252 | 4 | 2 | Point-to-point link |
| /32 | 255.255.255.255 | 1 | 1 | Single host / loopback |
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