When we talk about the size of pediatric blood pressure cuff that should be used on infants and very small children, the measurement comes in at 4×8 cm for newborns, 6×12 cm for infants and 9×18 cm for older children. This size of pediatric cuff is one that has been tried and tested and it has worked for many different sizes of infants. The size of the cuff will change slightly as a baby grows larger because the amount of room that you will have to work with when it comes to getting an accurate reading is going to be smaller. However, for smaller infants this is a good size that will allow for the proper placement of the cuff on the arm.