The size and shape of full-sized cellos is far more variable than that of violins. Although these differences may seem small compared to the size range of part-sized cellos, they can feel huge to a sensitive adult player.
Back length is not the only significant factor in cello size: the widths of the upper and lower bouts, the string length and the length of the neck relative to the string length also have a considerable impact on the player. Cellists can also grow accustomed to the feel of a particular neck shape (particularly in 4th position) and this can be a major contributor to the feeling of comfort and security when playing an instrument.
The modern standard for back lengths is shown in the list below. The back lengths shown for full-sized, ⅞, ¾, ½, ¼ and ⅛ sized cellos are based on average measurements; each cello size can vary up to 10mm or ½” either side of the average.
Back Length Measurement
Back length is traditionally used to determine the size of stringed instruments. To measure back length, place one end of the tape measure level with the very outer edge of the bottom of the cello at the centre line, stretch the tape over the length of the back and finish measuring at the extreme edge of the instrument just beside the button (the button is not included in the length measurement).
Since the tape lies over the arching of the instrument, the tape-measured length will be slightly greater than a true straight-line measurement. However, this error of a few millimetres is understood in the standard measurements shown in the chart below. It is safest to use a cloth dress-maker’s tape rather than a metal version when measuring instruments as cloth tapes are less likely to damage the varnish.
Standard Cello back lengths
Full-Sized 30 inches 760mm
Seven-eighths 29 inches 730mm
Three-quarters 27 inches 690mm
Half 25 inches 650mm
One quarter 23 inches 580mm
One eighth 21 inches 530mm
© Robin Aitchison 2005. Published in News for Cellists Autumn 2005