Can a 3 year old be weighed in grams?

Yes, a 3-year-old can be weighed in grams, although it is more common to use kilograms or pounds for measuring a child's weight. To convert the weight from kilograms to grams, simply multiply the weight in kilograms by 1,000. For example, if a child weighs 15 kilograms, that would equal 15,000 grams.