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IP Subnet Calculator
Calculate network information from an IPv4 address in CIDR notation.
Overview
Calculates the network address, broadcast address, usable host count, and more from an IPv4 address in CIDR notation (e.g. 192.168.1.0/24).
Even if you enter an address with host bits set (such as 192.168.1.200/24), it is automatically normalized to that subnet's network address before calculating.
Also handles special prefix lengths such as /31 (a point-to-point link per RFC 3021) and /32 (a single host).
Usage
- 1
Enter an address in "IP address/prefix length" format (e.g. 192.168.1.0/24).
- 2
Click "Calculate".
- 3
The network address, broadcast address, subnet mask, usable host count, and more are displayed.
Example
Input
192.168.1.10/24
Output
Network: 192.168.1.0 / Broadcast: 192.168.1.255 / Usable hosts: 254
Use Cases
Checking the usable host count and address range of a subnet being allocated during network design
Understanding the actual network range from a CIDR notation found in a server or router configuration
Verifying subnetting calculations before writing them into a design document
FAQ
What happens if I enter an address with host bits set (e.g. 192.168.1.200/24)?
It is automatically normalized to that subnet's network address before calculation.
How are /31 and /32 handled?
/32 is treated as a single host (network, broadcast, and host are all the same address). /31 is treated as a point-to-point link per RFC 3021, where both addresses are usable.
Is IPv6 supported?
Currently only IPv4 is supported.
Notes
Currently only IPv4 is supported. IPv6 addresses cannot be handled.
/32 is treated as a single host (network, broadcast, and host are all the same address).
/31 is treated as a point-to-point link per RFC 3021, where both addresses are usable (its usable host count is counted differently from a normal subnet).
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