Why Guitar Frets Sit Where They Do

Each fret on a guitar neck is placed so it divides the remaining string length by the 12th root of 2 (about 1.0595). That single ratio produces 12 equal semitones per octave — the system that lets you play in any key without retuning.

Before equal temperament, musicians used Pythagorean tuning (pure 3:2 fifths) or just intonation (pure ratios like 5:4 for major thirds). These sound cleaner in one key but badly out of tune in others, producing the dreaded wolf interval that makes certain key changes painful to hear.