If your scale needs to be calibrated, you essentially need to set it back to zero. Remove all the batteries from the scale and leave them out for about 10 minutes. \
Clean the battery compartment and contact terminals to get rid of any dust and debris that may be in there. Re-insert the batteries. \
Place the scale on a flat, level, even surface. Activate the scale by pressing on it with your hand. \
You may see a series of dashes or other symbols and then 0 should appear in the display. Test your scale with an item that you know the weight of to see if the scale is reading accurately now. \