1. Fill in purchase information

2. Confirm your information

3. Pay by credit card

4. Get receipt and log in


Please select a package to buy

Please check that you are purchasing the package that you need. Our packages are not interchangeable. In particular, registration keys for one package will not allow you to use the Grade Grinder to assess exercises from other packages.


Please choose the appropriate operating system.

You are responsible for ensuring that your computing platform meets the requirement for running the software. We support most current versions of the Windows and Macintosh operating systems. The Language, Proof and Logic and Tarski's World packages are available on Fedora and Ubuntu Linux platforms, but are not supported. We have no plans to support Logical Reasoning with Diagrams and Sentences on any Linux platform. See the FAQ for more details.

We do not support Chromebooks, phones or tablets.


Please fill in your personal information for purchase

The purchased products will be registered to the given name and email address. Registration is non-transferable.

Paperless Package