1) Take off right cover 2) Push cal switch while pressing on/zero. 3) Press enter until display reads CAL? 
4) Press enter then enter a 0 to bypass or 1 to enter cal. 5) Press enter, display shows C1, press enter, a number is displayed. 6) Press enter, CAL 1 is displayed, press enter, if this is your zero then enter 0 and press enter. 7) If CAL 1 is your load then enter the test weight used for calibration then press enter. 8) CAL 2: If CAL 1 was 0 then this will be your load or test weights, enter the value of the calibration weight and press enter. 9) If this is your zero then press enter and ensure the number displayed is 0 and that no load is on the platform, then press enter. 10) Press enter until Done is displayed then press off then on/zero.***** FINE SPAN::::With power applied and displaying weight, press and hold the calibration switch on the printed circuit board.  Then press 0 to decrease span or 1 to increase span.