Address (Host or Network) Netmask (i.e. 24) Netmask for sub/supernet (optional)
/ move to:
  



Address:   10.1.1.0              00001010.00000001.00000001 .00000000
Netmask:   255.255.255.0 = 24    11111111.11111111.11111111 .00000000
Wildcard:  0.0.0.255             00000000.00000000.00000000 .11111111
=>
Network:   10.1.1.0/24           00001010.00000001.00000001 .00000000 (Class A)
Broadcast: 10.1.1.255            00001010.00000001.00000001 .11111111
HostMin:   10.1.1.1              00001010.00000001.00000001 .00000001
HostMax:   10.1.1.254            00001010.00000001.00000001 .11111110
Hosts/Net: 254                   (Private Internet)

Thanks to http://www.netzwerkinfo.de/daemons/ for this ip calculator icon :-)
Version 0.35.2 2005/07/07
Download
07/27/2006 Security information
Screenshot (ipcalc works also at the prompt)
CGI wrapper that produced this page.
Archive
Have a look in the archives for the new version 0.41, with the capability to deaggregate network ranges
How to run this under windows
Debian users can apt-get install ipcalc
2000-2006 Krischan Jodies