The correct tonfa size is critical for the maximum performance from the tonfa.  Most mail order companies offer just small or large tonfas. Like one size fits all.  To work this weapon correctly, like any other weapon, it needs to be sized to you.

 If you are a school or organization Crane Mountain makes a tonfa measuring stick for sale at a nominal fee. The Measuring stick will provide a more accurate measurements of the hand and elbow lengths.
Pasted Graphic

      An alternative method of measurement, is using a carpenters square. By gripping the square’s narrow column as illustrated by the drawing below. The length of the elbow can be obtained by the inside square measurement plus one half the thickness of the column.. The measurement for the hand can be obtained by the inside tick marks of the column and subtracting the 1/8 of an inch.

The measurements to use when calling in an order are : 1) The elbow length and 2) the hand size.  Specify the elbow length plus extension beyond the elbow your school or system requires.  It is typically an inch for most Kobudo schools.  Please give us the elbow size and extension as 2 separate  measurements. I.E. 13 + 1. Standard sizes for handles are in 1/4 inch increments and blade lengths are in 1/2 inch increments. Extra  charge for custom lengths outside these parameters.