As shown in the picture, measure from the neck to mid palm of the left hand. The length of the arm will determine the size your child needs.  

1/4 size: 18"

1/2 size : 20" arm length 

3/4 size: 22" arm length 

4/4 size: 23" + arm length 

As shown in the picture, measure from the neck to mid palm of the left hand. The length of the arm will determine the size your child needs.  

12" size: 20" arm length 

13" size: 22" arm length 

14" size: 23"-24 1/2" arm length 

15" size: 24 3/4"-25 3/4" arm length 

Cello sizing is based on the height 

1/4 size: Under 48" height 

1/2 size:  48"-54" height 

3/4 size: 54" height-60" height 

4/4 size: 61" height and above 

Bass sizing is based on the height 

1/4 size: 4 - 4.5 ft

1/2 size: 4.5 -5.5 ft