I would like to add worksheets to the windows 7 calculator. Is that possible? I'm thinking about a medical calculator, among others for the BMI, kidney function and several unit conversions (from mmol/l to mg/ml for example, or fluid calculations per unit of time)

wevenhuis, The Windows calculator has always been a relatively simple, standalone application. Although it's been expanded more in Windows 7 than it had been since Windows 95, there is no way, to the best of my knowledge, for an end-user to add features. You might try the freeware application Calculator++ - or, of course, there's always Microsoft Excel.-Alex