Q: How can I calibrate my scale? The number I get when I use it is different from the number shown at the doctor's office or at the health club.
A: You need answers to these questions:
Does the scale repeat itself every time the same weight is applied? (It should.)
Does the weight change when you lean forward, then backward? (It shouldn't.)
Is the scale starting on zero before weight is applied? (It should.)
If your scale doesn't pass those simple tests, problems other than calibration may be affecting its accuracy.
If it does, then the scale probably is stable and needs to be calibrated.
Low-profile bathroom dial scales usually will have an adjustable spring inside the main housing. To get at that spring, remove the two cover screws or small springs holding the top and bottom together.