Baby clothing sizes are usually based on age: preemie, 0 to 3 months (newborn), 3 to 6 months, 6 to 9 months, 9 to 12 months, 12 months, 18 months, and 24 months.

Baby clothing sizes are determined based on height and weight and are listed according to age. A general rule of thumb is to choose the clothing size that coordinates with your baby's age.

Average baby weight can vary by the sex assigned at birth. But the weight of babies who are healthy and full-term can be over or under the average. Babies come in all shapes and sizes. Weight can ...

Weight is a better measure, and it is listed along with age on many baby clothes. Think about how easy clothes will be to put on and take off. Dressing a wiggling newborn can be a bit of a struggle.