Selecting the perfect size for your baby is essential for their comfort and mobility. We have a size guide available on each of the product pages on our website that provides specific measurements to help you make the right choice. Additionally, all of our sizing is done by age range making it easy for you to choose. Shhhh.. we'll let you in on a little secret - our clothes are wonderfully stretchable which means they'll often last longer than the stated age range, or if your baby is slightly bigger than average, they will stretch to ensure a lovely comfy fit for your baby.