The number of diapers you'll need for your baby will depend on how often you plan to change your baby and how quickly your baby grows. As a general rule, newborns will need about 10-12 diapers per day, while older babies may need fewer. If you are planning to have a baby shower, I recommend asking for as many diapers in various sizes as possible. You likely won’t need many newborn diapers depending on your baby’s size at birth.