Netcalc

Usage:  netcalc ip/mask | ip dot.ted.quad.mask

netcalc will calculate Network Address, broadcast address, the # of
IPs between them and the Cisco Wildcard, when given an IP Address in
CIDR format or with conventional dotted quad Netmask.

To save typing, you can omit octets, which will be "0".  "173" gets
"173.0.0.0".  "255.255" gets "255.255.0.0".

Strings with a leading dot will be filled with zeroes for IPs and with
"255" for DQ-Netmasks. ".240" is the ip address "0.0.0.240", or the
netmask "255.255.255.240"

These inputs will be the same: "10.10.0.0/16" and "10.10.0.0 255.255.255".
"10.10/16", "10.10 255.255" and "10.10 .0.0".

Use ".173/29", ".173 .248", ".25.173.240.0" if you don`t care about
the other octets.