Violins come in "fractional sizes" (4/4, 3/4, 1/2, 1/4, 1/8, 1/16, even a tiny 1/32). The 4/4 is full size, suitable for nearly all adults. The 7/8 size is rather rare, and only available in the more expensive instruments. It is frequently used by adults who are very petite. [Please see: K500 Student Outfit available in 7/8]
Violas: While violins come in fractional sizes, violas are measured in inches (17", 16 1/2", 16", 15", 14", 13", 12"). For students changing from violin to viola, or adding viola after studying violin, the 14" viola is approximately the same size as a full size violin. Many violists start on violin. [Please see our Peccard Viola Outfit]
The 16" is the usual adult size. Any size above the 16" may be difficult to handle for young people and is probably not recommended. Viola length is measured in centimeters in Europe (41cm, 41.5cm and 42cm), and there is no exact standard with respect to size. Many professional violists play a 17" viola; Michael Tree (of the
Guarneri Quartet), Bruno Giuranna, Gerard Coussè.
The viola is a fifth lower in pitch than the violin; the lowest string on the viola is the C string. The viola's second string, the G, is the violin's lowest string. Violas have no E string, the top string on violin. The A=440 (the violin's second string), is the top string on viola. The viola is primarily written in the alto clef (though high registers may be written in treble, like the violin). See:
Note that the viola is "not just a big violin." Violists will have you assassinated if you even think that. Playing the viola requires a very different touch, different fingerings, different position work, different vibrato, and an entirely different mindset with respect to its role in the orchestral and chamber music repertoire. Violists are very sensitive about this.