With the student’s left arm fully extended and palm up, use a measuring tape and measure from the chin touching the neck to the center of the palm.
Up to 17.25 inches is a 1/4 size violin/viola
Up to 19.25 inches is a 1/2 size violin/viola
Up to 21 inches is a 3/4 size violin/viola
Up to 22 inches is a 4/4 size violin/viola
Your student's height can be used to determine the proper cello size.
4 feet - 4 feet 6 inches is a 1/2 size cello
4 feet 6 inches - 5 feet is a 3/4 size cello
5 feet and up is a 4/4 size cello
Your student will start on a 1/4-size bass.