Network Tools
IP Subnet Calculator
IPv4 subnet calculator: network, broadcast, masks and host range from CIDR.
Runs in your browser Your input never leaves your device.
About this tool
Calculates the details of an IPv4 subnet from an address in CIDR notation, such as 192.168.1.0/24. It shows the network address, broadcast address, subnet mask, wildcard mask, the prefix length, the number of usable hosts and the first-to-last host range. Any address inside the subnet works as input; the tool finds the network for you. For /31 networks it reports 2 usable hosts and for /32 it reports 1, and it does not show a host range for those. Despite the general name, it handles IPv4 only; IPv6 input is not accepted. All math runs in your browser.
How to use it
- Enter an IPv4 address with a prefix length, like 10.0.0.5/30.
- Read the network and broadcast addresses and the masks.
- Check the usable host count and range for planning your addressing.
Example
Input
10.0.0.5/30
Result
Network address: 10.0.0.4 Broadcast address: 10.0.0.7 Subnet mask: 255.255.255.252 Wildcard mask: 0.0.0.3 CIDR: /30 Usable hosts: 2 Host range: 10.0.0.5 – 10.0.0.6
Common problems
- Nothing is shown
- The input must be four numbers from 0 to 255, a slash, and a prefix from 0 to 32. Enter it as CIDR, not as a mask.
- Invalid IPv4 CIDR
- An octet is above 255 or the prefix is above 32. Fix the value and try again.
- IPv6 address entered
- The tool supports IPv4 only.