Guitar Frets are laid out to accomplish an equal tempered division of the octave. Each set of twelve frets represents an octave. The twelfth fret divides the scale length exactly into two halves, and the 24th fret position divides one of those halves in half again. The ratio of the spacing of two consecutive frets is formula_1 (twelfth root of two). In practice, luthiers determine fret positions using the constant 17.817—an approximation to 1/(1-1/formula_1). If the nth fret is a distance x from the bridge, then the distance from the (n+1)th fret to the bridge is x-(x/17.817). Frets are available in
Zero fret continue perpetually. Some manufacturers that frequently use(d) a zero fret are Gretsch, Kay, Selmer, Höfner, Mosrite, Framus, Vox, Vigier and bass guitar manufacturer MTD. Now very few manufacturers use this design and those who do list it as a feature. Steinberger uses a zero fret with their headless guitars but omit the nut; strings are mounted in place where the head would normally be, so there is no need for the string guides that the nut provides. 2015 model year Gibson guitars incorporate a zero fret in order to accommodate a brass adjustable nut, which the manufacturer claims causes better