When building a guitar neck, it is important that the frets are placed correctly. As the length of the vibrating string is halved, the frequency doubles, and we hear a sound one octave higher than the open string. There are 12 notes in an octave(including sharps & flats) and the formula to break the octave up into 12 pieces is to divide the length by [math]2^\[\frac{1}{12}\][/math] If you input the length of your guitar neck, this will let you know the distances from the bridge to the fret for each note.