FAQ: Inaccurate readings

The weight printed on food packaging refers to the average weight of the food in the container excluding the container itself.  So a 14 oz. can of soup placed on the scale will weigh more than 14 ounces because the weight of the can and the compressed air is also being measured.  

Also keep in mind that many liquids are measured in fluid ounces rather than weight ounces.  Your scale will only display ounces of weight.