Calcute is a good replacement for the Windows calculator. It is a handy expression evaluator, compact but capable. It is also a freeware program.
Calcute lets you evaluate complex expressions like: -ln(pi) * acosh(2 1/3 ^ e) by typing them directly in its work area. It supports logarithmic, trigonometric and hyperbolic functions. It can be used in a tiny single-line mode or an editable multi-line mode like a tape calculator. Stretch its editable area to any size, show the keypad or hide it.
A number of interesting features make it a capable tool, but Calcute remains a simple calculator. It will be convenient for anyone who needs to do basic calculations. This program is officially hosted at Calcute.com but you can also download its setup program from here.