CIDR Calculator
Calculate IP subnet information from CIDR notation. Find network address, broadcast address, subnet mask, host range, and usable hosts.
Enter CIDR notation (192.168.1.0/24) or IP with subnet mask
Common Subnet Reference
| CIDR | Subnet Mask | Usable Hosts |
|---|---|---|
| /8 | 255.0.0.0 | 16,777,214 |
| /16 | 255.255.0.0 | 65,534 |
| /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 |
| /32 | 255.255.255.255 | 1 |
Click a row to try that subnet
CIDR Notation - Technical Details
CIDR (Classless Inter-Domain Routing) notation specifies IP addresses and their routing prefix. The number after the slash indicates how many bits are used for the network portion. For example, /24 means 24 network bits and 8 host bits, allowing 254 usable hosts.
Command-line Alternative
# Calculate subnet on Linux\nipcalc 192.168.1.0/24\n\n# On macOS (install with brew)\nbrew install ipcalc\nipcalc 192.168.1.0/24