In this video you can see the best way to measure your child's feet. Please remember to measure both feet, it's best to do it in the afternoon or evening. Remember that one size on average is 7mm. We don't recommend buying shoes that are bigger by more than one size. However for winter shoes we recommend you have 7-9mm in size group 20-25 and 1-1.5cm in the size group 26-31.