Bale measuring method for a rectangular baler includes the steps of: measuring a movement of a binding material that is being tied around a bale； using the measured movement of the binding material to calibrate a measurement and calculation tool for measuring a movement of the bale in the baler and for calculating a length of the bale based on said measurement； determining the length of the bale using the calibrated measurement and calculation tool as the bale moves backward in the baler.
