A method and system for automatically calibrating a pressure sensor in a hydrogen storage system for a fuel cell vehicle. A low-range pressure sensor in the fuel cell system, which has much greater accuracy at low pressure readings, is used to calibrate a high-range pressure sensor in the hydrogen storage system. This calibration can only be done when a pressure regulator situated between the two sensors is in a fully open position. In such a condition, the high-range sensor can be calibrated to the value of the low-range sensor, thus improving the accuracy of the high-range sensor's readings. The calibration can be a simple setting of the high-range sensor to the value of the low-range sensor under static conditions, or the calibration can be done while gas is flowing from the hydrogen storage system to the fuel cell by accounting for the pressure drop between the two sensors.