In order to run MOPAC, you will need to have it installed on the appropriate computer or computers. Please see the MOPAC website for further details. If you are at Viginia Tech, please contact Paul Saxe ( for access to the University-wide license. At other institutions it is possible that there is already a license that you can use. Otherwise, for academic users MOPAC is free, but requires a license which you can get from the MOPAC website.

Stable release

To install MOPAC step, run this command in your terminal:

$ pip install mopac_step

This is the preferred method to install MOPAC step, as it will always install the most recent stable release.

If you don’t have pip installed, this Python installation guide can guide you through the process.

From sources

The sources for MOPAC step can be downloaded from the Github repo.

You can either clone the public repository:

$ git clone git://

Or download the tarball:

$ curl  -OL

Once you have a copy of the source, you can install it with:

$ python install