How Many Diapers Do You Need And What Size? Welcome to our free and easy to use Diaper Calculator. This diaper calculator will help you estimate: How many diapers your baby needs, What size diaper per stage is expected from birth until potty training, Your total diaper costs, and A detailed price comparison between the most popular diaper brands. Diapering can get complicated, which is why moms and dads have so many questions. These are just a few commonly asked diaper questions from regular…