Subnet Host Count
Enter an IPv4 CIDR block and instantly see the network address, broadcast address, subnet mask, and number of usable hosts.
IPv4 CIDR Input
Enter an IPv4 address followed by a prefix length (0–32).
Quick Examples
Enter a CIDR block on the left to see subnet details.
Usable Hosts
0
Prefix
/24
Network Address
The first address in the subnet; identifies the subnet itself.
Subnet Mask
Dotted-decimal representation of the prefix length.
Wildcard Mask
Inverse of the subnet mask; used in ACL and OSPF configurations.
Broadcast Address
The last address; packets sent here reach every host in the subnet.
First Usable Host
Lowest IP address assignable to a device.
Last Usable Host
Highest IP address assignable to a device.
Total Addresses
All addresses including network and broadcast (2^(32−prefix)).
Mask in Binary
Summary
Enter an IPv4 CIDR block and instantly see the network address, broadcast address, subnet mask, and number of usable hosts.
How it works
- Enter an IPv4 address with a CIDR prefix length, e.g. 192.168.10.0/24.
- The tool derives the subnet mask from the prefix length (e.g. /24 → 255.255.255.0).
- The network address is computed by ANDing the IP with the mask.
- The broadcast address is the network address OR'd with the inverted mask.
- Usable hosts = 2^(32 − prefix) − 2 (subtract network and broadcast addresses).
- First and last usable host addresses are shown for quick reference.
Use cases
- Plan IP address allocation for a new network segment.
- Verify that a CIDR block is large enough for the expected number of devices.
- Look up the broadcast address before configuring firewall rules.
- Cross-check subnetting homework or certification exam practice.
- Confirm the usable range when setting DHCP pool boundaries.
- Convert a prefix length to dotted-decimal subnet mask quickly.