When you first download the app it gives you no decimal points. 100 megabytes is 0 gigabytes. The keyboard is hard to access, you have to drag up a small "handle" from the very bottom of the screen. It does have a lot of units though (it should say how often currency is updated). For easier ui, try Multi-Calc. It lets you type a number in one unit and converts it to all others so you can see and edit all of them.
Yankeexpress about Unit Converter™