I'm looking for a computer based scientific calculator that is fast and convenient for converting numbers back and forth between metric and imperial. What I imagine is a program with 2 additional windows (one for imperial and one for metric) where I can specify which types of units I want to see and it will convert what is in my calculator display to the opposite units in real time. Let's say for instance I was calculating some dimensions in inches, I would know that I put inches in. The metric window would be displaying the equivalent centimeters, sq centimeters, cubed centimeters etc. Conversely, if I was calculating in metric then the imperial window would be displaying the conversion in imperial units. It would be my responsibility to know what units I put in and therefore understand what units were being displayed. It would be so much faster than the method in the Mac calculator where you have to mouse up to the menu and select the conversion you want. Anyone use anything like this?