Business Functions is a free function library for Microsoft Excel that's been around since 2002.

It's for financial and business analysts in corporates, banks and property companies.

We built it to make business plans, budgets, structured financings and cashflows more powerful and manageable. Using standard functions makes models:

• more adaptable, because a single function call can invoke a large variety of different kinds of behaviour.
  
• more accurate, because, amongst other things, over the years we've built in quite a sophisticated date/time system that models daycount very accurately.
  
• faster to build, because you can build from an existing palette of standard algorithms, rather than reinventing the wheel every time.
  
• quicker to run, because of the fast language the functions are written in (C++).
  
• less error prone, because of the standard and tested behaviour of the functions. Be aware, that it doesn’t eliminate the cause of spreadsheet errors.
  
• more transparent and understandable, because the function's name and documentation explains the intent of what's being modelled better than a hieroglyphic formula.