It's very easy to use, it is intuitive for anyone who has used any other calculator or spreadsheet program before this one! The interface could be more user friendly (it looks like something from 10 years ago). I'm using some of these functions in my work everyday so that makes me happy as well :) Great product with great support team behind you if needed at all times!! Highly recommendable tool especially when working through calculations related projects such us engineering design process etc., where accuracy matters most!