Fraction Sizes Explained: How to Pick the Right Size?

The following charts will help you decide which size instrument is appropriate for your student.

  • If you already know what instrument size you need or have already been sized by your teacher, you may disregard these charts, and select your size in the appropriate field below;
  • Please note that the measurements and age ranges given here are averages, and may not directly translate to your student; if your student is, for example, tall for their age or perhaps has very small hands, the charts may not be accurate for them;
  • If your student falls in between or overlaps with two sizes, we recommend choosing the smaller of the sizes. Trying to learn on an instrument that is too large is not only uncomfortable, but can be very frustrating for the student and even cause long term injury;
  • If you have any questions about sizing, you are always welcome to our shop where one of our knowledgeable staff will be happy to assist you in sizing your student;
  • If you happen to choose the incorrect size, don't despair! We offer size exchanges at NO CHARGE, and in many cases we can arrange to bring the new size directly to your student's school. Please contact us to inquire about this service.

Picking the Right Size: Violin and Viola

To measure the arm length, have the child stand up straight with their left arm extending straight out to their left, palm open upwards.

Start measuring at the neck and stop the measurement in the middle of the child's palm (see Figure on the left).

Use the arm length (in inches) in combination with the child's age to find out the correct size of violin or viola that you need to rent from the Table 1 below.

 Age Group (years)
 Arm Length (inches)
 Violin Size (fractions)
 Viola Size (inches)
Under 3
 13"  1/32  
3-5  14"  1/16
4-5  15"  1/10
4-6  16-17"  1/8  10"
5-7  18-19"  1/4  11"
7-9  20"  1/2  12"
9-12  22"  3/4  13"
12 and above
 23"+  4/4  14"
 25-26"  15-1/2"
15-16  26-27"  16"
 16 and above
27"+    16-1/2"

Table 1. Violin and Viola fractional sizes in relation to student's age and arm length.

Picking the Right Size: Cello and Double Bass

In order to determine the correct cello or double bass size for your child, please measure his or her height and use that as a starting point in combination with the child's age. Reference the Table 2 below in order to determine the correct size.

It goes without saying, however, that the chart below can only give you an approximation of a height, age, and instrument size relationship as every child is unique!

Finally, renting an instrument from us allows you to switch between fractional size instruments without an additional charge. Please contact us if you have any questions regarding this and the above table.

Age Group (years) Height (feet)
 Cello Size (fractions)
 Double Bass Size (fractions)
 3-5  Under 3'
4-6  3' - 3'6"
5-7  3'6" - 4'
 1/4  1/8
7-11  4' - 4'6"
 1/2  1/4
11-15  4'6" - 5'
 3/4  1/2
15 and above
 5' and above
 4/4 (full size)
Table 2. Cello and Double Bass sizes in relation to height and age.