•Measure your baby's feet with socks on, from the tip of the big toe to the heel. •Measure both feet and use the larger of the two measurements, to select the size. •Toddlers tend to curl their toes when you try to measure, so make sure the feet are flat, preferably while they are standing. •The ½" recommended comfort space, is already built into our sizing charts -No need to add to your measurements.