Hi agapetos,
Here's some information from the "wikipedia" regarding violin sizes.
"Sizes
Children typically use smaller string instruments than adults. Violins are made in so-called "fractional" sizes for young students: Apart from full-size (4/4) violins, 3/4, 1/2, 1/4, 1/8, 1/10, 1/16, and even 1/32-sized instruments exist. Extremely small sizes were developed, along with the Suzuki program for violin students as young as 3 years old. Finely-made fractional sized violins, especially smaller than 1/2 size, are extremely rare or nonexistent. Such small instruments are typically intended for beginners needing a rugged violin, and whose rudimentary technique does not justify the expense of a more carefully made one.
These fractional sizes have nothing to do with the actual dimensions of an instrument; in other words, a 3/4-sized instrument is not three-quarters the length of a full size instrument. The body length (not including the neck) of a "full-size" or 4/4 violin is about 14 inches (35 cm), smaller in some 17th century models. A 3/4 violin is about 13 inches (33 cm), and a 1/2 size is approximately 12 inches (30 cm). With the violin's closest family member, the viola, size is specified as body length in inches or centimetres rather than fractional sizes. A "full-size" viola averages 16 inches (40 cm).
Occasionally, an adult with a small frame may use a so-called "7/8" size violin instead of a full-size instrument. Sometimes called a "lady's violin", these instruments are slightly shorter than a full size violin, but tend to be high-quality instruments capable of producing a sound that is comparable to fine full size violins.
Violin sizes are not standardized and dimensions vary slightly between makers."
For further information you can visit the following site:
http://en.wikipedia.org/wiki/ViolinIf you’re thinking of making a violin may I suggest the "Art of Violin Making" by Chris Johnson. An excellent book but it can be expensive.
Regards,