I make a lot of propellant to fly my rockets, and having all of my propellant information in one place really helps speed things up. BatchBook is based loosely on an Excel file included with Dr. Terry McCreary's text, but is completely rewritten from the ground up to focus on usability and ease of reference.
All formulas are consolidated into a single spreadsheet to simplify bookkeeping, and a variety of geometries for widely-available motor hardware are included to make sizing a batch as simple and repeatable as possible: pick a formula, pick a motor size to cast, and the book handles the rest. Formulation density is calculated on the fly from an included list of ingredients.
More advanced binder capabilities are built in as well, with a binder and curative equivalent weight reference library to allow changes in polymer chemistry with ease.
If you're interested in suggesting new features or helping me polish it up, let me know and I can send you a copy.