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

We think it makes business plans, budgets, structured financings and cashflows more powerful and manageable. We found that 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 time periods very accurately.
  
• faster to build, because you can build from an existing palette of standard algorithms, rather than reinventing the wheel every time. Its more of a building block approach.
  
• more consistent, because the building blocks get repeated across the model and other models.
  
• quicker to run, because of the fast language the functions are written in (C++).
  
• probably 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, it probably restricts the errors to bugs in functions (yes it can still happen) and your misuse of them, which, to us, is preferable to wading through lots of spaghetti spreadsheet logic.
  
• more transparent and understandable, because the function's name and documentation explains the intent of what's being modelled better than a hieroglyphic formula.
  

Business Functions is a comprehensive collection of projections functions for projecting cashflows and accruals with a high degree of daycount accuracy.

The 500 or so functions do the dirty work of projecting costs and revenues, coping with time periods, growth etc. In many contexts it is a complete solution, allowing models to dynamically run on any timebase (quarterly, annually etc) by changing a single cell.

You might want to look at our attempted objective assessment of the Business Functions in