Hi Paul,
Based on your description, it sounds like you are looking for a simple webpage that takes a few inputs (initial amount, amortization period, etc) and outputs a table on the page itself. If this is indeed all that you need, then this would be most simply implemented in Javascript right in the browser. However, if you would like to pull data from the server, or would like to persist the data, then a lightweight web app based in Flask would probably meet your needs better than Django. So far as the displaying of data in the browser goes, there are several fine libraries for displaying and working with tabular data; I'd be happy to work with you to find the right solution.
This sounds like a well-defined project that can be implemented cleanly. Feel free to contact me so that we can discuss your needs further. Look forward to hearing from you.
Cheers,
Malcolm