1. Remove one of the batteries and put it back in. This refreshes the scale. Turn on the scale.
2 Press the mode for three seconds, 'CAL" will appear, release the mode button.
3. The capacity of the scale will appear "20.000" and flash
4. Put 20 gm weight on scale, be sure it is centered on the scale. (do not worry about what the scale says at this point, it might be off by a bit.)
5. "Pass" will show briefly, and the 20.000 will show without flashing.
6. Turn off scale. Calibration is done.
If the above doesn't work, try these:
1. Under power off condition, Press “MODE” and “TARE” simultaneously unreleased until the display show “CAL”.
2. After the data be stable, press” TARE", then it displays"0.000g”.
3. Put the standard weight of "20g"on the scale.
4. Press "TARE" after the digital display is stable. Then it displays"20.000g".
5. Press "TARE" again. Then it displays” PASS”. And power off automatically. And the calibration finished.
These calibration directions for this scale on this page