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How to Calibrate a Scale Without a CAL Button

Some digital scales include a "CAL" button or mode setting that automatically calibrates the scale when an item of a known weight is placed on it. However, not all digital scales have this feature, and almost no analog or balance scales can be calibrated automatically. Nevertheless, you can calibrate any scale so long as you have an object for which you know the weight. You just need to check the weight reading for that object on your scale and adjust the scale so that the reading matches the known weight of the object.

Things You'll Need

100-gram (3.572 ounce) calibration weight

Instructions

- 1
  Turn the scale on if it is a digital scale. Set the scale to its zero setting.
- 2
  Place a 100-gram calibration weight on the scale's balance plate or other weighing compartment. Set the weights on a beam balance to 100 grams or 3.57 ounces.
- 3
  Check the reading of the scale. If set to metric, the scale should read 100 grams and if set to English weights the scale should read 3.57 ounces. The beam of a beam scale should show as exactly balanced.
- 4
  Subtract any lower reading from 3.57 ounces or 100 grams. Subtract 3.57 ounces or 100 grams from any higher reading. Note the difference and whether it reads high or low.
- 5
  Remove the weight from the scale and allow the scale to go back to zero. Locate the adjustment screw or button of the scale and set it so that it increases or reduces the weight by the necessary amount.
- 6
  Place the weight on the scale again and make sure it shows the correct reading. Readjust the screw or button if necessary. Once the reading on the scale matches the 3.57 ounce or 100-gram weight of the scale, you can use the scale knowing that it reads the exact weight.

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