tkalc

tkalc is a pocket calculator for developers and IP network operators. Arbitrary arithmetic or logical expressions can be entered very quickly in a text entry field. The result is then simultaneously displayed in decimal, hexadecimal, octal, binary, ASCII, IP address, and Boolean format. It accepts all number formats, operators, and functions that can be handled by the Tcl interpreter and extends this even further for input of IP addresses and binary numbers. (Source: http://freecode.com/)