Enter an IP address and CIDR prefix to get the network, netmask, broadcast address, host range and host count.
How this calculator arrives at its answer
This subnet calculator breaks down an IPv4 network. Enter an IP and its CIDR prefix (like /24) and it returns the network and broadcast addresses, the netmask, the usable host range and how many hosts fit.
It’s a everyday tool for network setup and study.
Getting your answer
- Enter an IPv4 address.
- Enter the CIDR prefix length.
- Read the network, broadcast and host details.
Formula reference
network = IP AND mask · broadcast = network OR ~mask
usable hosts = 2^(32−prefix) − 2
Try it with these numbers
Take the starting scenario, a IP address of 192.168.1.10, CIDR prefix of 24. That gives a network of 192.168.1.0/24. Underneath, Netmask comes out at 255.255.255.0 and Broadcast at 192.168.1.255. Change any field and every figure updates as you type.
Questions people ask about this
What does /24 mean?
The CIDR prefix — how many bits are the network portion. /24 means a 255.255.255.0 mask with 254 usable hosts.
Why subtract 2 from the hosts?
The network address and the broadcast address can’t be assigned to devices, so they’re excluded.
What is the broadcast address?
The last address in the subnet, used to reach every host on that network at once.