Subnet Calculator
Enter an IPv4 address and mask to get the network and broadcast addresses, usable host range, host count, and wildcard mask.
Processed locally in your browser — nothing is uploaded.
Enter an address and mask to see the subnet.
About Subnet Calculator
Give it any address inside a subnet plus the mask — as a prefix (/26) or in dotted form (255.255.255.192) — and it works out the network address, the broadcast address, the first and last usable host, and how many hosts the subnet holds.
The wildcard mask is included for ACLs and route maps, along with the address's traditional class and whether it falls in a private, loopback, link-local, or carrier-grade NAT range. The /31 and /32 edge cases follow RFC 3021 rather than blindly subtracting two.
Common uses
- Work out the usable host range before assigning static addresses
- Translate between a dotted netmask and a CIDR prefix
- Get the wildcard mask for a firewall or router ACL
Example
Input
192.168.1.130 · /26
Output
Network 192.168.1.128 · Broadcast 192.168.1.191 · Hosts 192.168.1.129–192.168.1.190 (62)
Limitations
- IPv4 only — IPv6 uses different arithmetic and has no broadcast address
- Address class is legacy information; routing has been classless (CIDR) since the 1990s