UGG Mel Series Lace-free Plus Velvet Children's Shoes Size Chart Measuring the foot length is the key to size selection. Different brands and different series of shoes will have different shoe sizes. Be sure to measure the baby's foot length and compare the foot length with the size chart [Reference Suitable for foot length] Choose the number of sizes. The child's foot length will change when he is 3 months old. Spend an extra minute choosing the size and save a week of changing sizes. Snow boots, boots