Wait for the display to show ''0.000g'', the press and hold ''M'' Key till the display shows ''50.000'', then release.
Press ''M'' Key again, display will flash ''50.000'' followed by the required calibration weight.
Place the required calibration weight on the center of the platform, display will show "PASS", then turn off the scale and take down the Calibration Weight..
Calibration is complated! Repeat above steps if something goes wrong.