You have to press the "Unit" button (on the right) continuously until you get to the unit of measurement in which you would like to view the reading. So, for example, if your scale is reading in ounces, you would press the "Unit" button if you want it to read in pounds, then again if you want to see the reading in grams, then again if you want to see it in kilograms. HTH!
You can scroll through all of the different units of measurements by simply pressing the "unit" button while your item is on the scale. You do not need to start over if you want to change units. You can also scroll to the unit you want prior to placing the item on the scale. It will automatically start with the previously used unit next time you turn it on.