This calculator is presented for educational purposes only. You, as pilot in command, are solely responsible for assuring correct data and proper loading of your aircraft prior to flight.
Empty weight and C.G. data comes from your AC current weight & balance records.
Station arms, load limits, and airspeed limits come from the Airplane Flight Manual (before 03-01-79) or Pilot's Operating Handbook [POH] (after 03-01-79) [pop-up more detail], or the FAA Type Certificate Data Sheet (TCDS). Downloading the TCDS is recommended to learn more about your AC.