Calc4M is a multi function calculator for Java mobile phones. Besides basic calculations it allows you to calculate trigonometry, logarithms, functions, and more.
You'll find all the usual functions of a scientific calculator within Calc4M (sine, cosine, square root, cubic root, etc.) as well as the standard arithmetic functions. Each button on the calculator represents a different key on your phone. Tap to enter a number or hold down the appropriate key to apply a function.
Delve into Calc4M's menu and you can switch between arithmetic and scientific keyboard layouts. There's also a pre-installed list of selectable constants (speed of light, Coulumb's constant, electric constant, etc.) that can be quickly selected for use in equations.
Other features of Calc4M include battery level display, full screen mode, and changeable font sizes. Unfortunately, the interface in Calc4M is quite ugly, though.
Calc4M makes for a powerful, easy to use calculator for your phone.