Tool Subnet Calculator
Work out an IPv4 subnet
Enter any address in the subnet and its prefix length. You can also type both together, such as 192.168.10.37/27. The result updates as you type.
Subnet details
| Network (CIDR) | |
|---|---|
| Subnet mask | |
| Wildcard mask | |
| Network address | |
| Broadcast address | |
| First usable host | |
| Last usable host | |
| Usable hosts | |
| Total addresses | |
| Address type |
About the Subnet Calculator
A subnet divides an IP network into smaller blocks. The prefix length in CIDR notation, such as /24, says how many bits identify the network; the rest identify hosts. A /24 has 256 addresses, of which 254 can be given to devices.
Enter any address in the subnet with its prefix length and this calculator shows the network and broadcast addresses, the subnet and wildcard masks, the first and last usable host, and how many hosts fit. It runs entirely in your browser and updates as you type.
Frequently asked questions
254 usable hosts. A /24 contains 256 addresses, but the first is the network address and the last is the broadcast address.
255.255.255.224, giving 32 addresses and 30 usable hosts per subnet.
The inverse of the subnet mask, for example 0.0.0.255 for /24. It is used in router access lists and some firewall rules.