How to determine what size Violin to buy
To measure what size violin best suits you, you need to know the length between your neck and the middle of your left-hand palm (when your hand is fully extended and raised perpendicular to your body, just like holding a violin). The violin size determined by the neck/mid-palm measurement is the biggest size students should use.
SIZE 4/4 3/4 1/2 1/4
AGE 11-adult 9-11 6-10 4/7
ARM  Length 23.5 and up 22-23.5 20.375-22 18.5-20.375