### DiaperPlanner.com - Diaper Calculator

Diaper Sizes. Size NB/Newborn (Up to 10 lb) - For small or average-sized newborn infants.; Size 1 (8-14 lb) - For larger newborns and infants up to 3 months old.; Size 2 (12-18 lb) - For infants from 2 to 6 months old.; Size 3 (16-28 lb) - For infants and toddlers from 5 months to 2 years old.; First Year Average Diapers Per Day. 0-3 Months up to 10/day; 3-6 Months up to 7/day