An system for calculating blood pressure may include a sensor system and a control system. The control system may be capable of controlling one or more sensors of the sensor system to take at least two measurements, the at least two measurements including at least one measurement taken at each of two or more different measurement elevations of a subject's limb. In some examples, the control system may be capable of determining a blood flow difference based on the at least two measurements, of determining a hydrostatic pressure difference based on the two or more different elevations of the at least two measurements and of estimating a blood pressure based on one or more values of blood flow, the hydrostatic pressure difference and the blood flow difference.
