This calculator is noteworthy in that it employs a stack model of computation (Reverse Polish Notation), it supports numbers with SI scale factors and units, and uses a text-only user interface.
There are two versions, one (ec) that requires Python 2.7 or Python 3.3 or later and another (ec0) that has been tested to run on Python versions as early as 2.3.
The source code for the two versions are hosted on GitHub. Choose either ec or ec0. Read the README and INSTALLING files for a description of how to download, test, and install the program.
By default EC is configured to be a calculator for electrical engineers. It is possible to configure it so that it is tailored for other disciplines (see CUSTOMIZING). Once configured, it will regenerate is manpage to match the new configuration. The manpage for the default configuration can be found below.