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.
Report a problem with this tool
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.