Equal temperament is the tuning system underlying almost all modern Western music. It divides the octave into twelve equal steps, so that each semitone multiplies the frequency by the twelfth root of two, roughly 1.0595. Twelve such steps multiply the frequency by exactly two, closing the octave perfectly. The great advantage is uniformity: because every semitone is identical, an instrument tuned this way sounds equally acceptable in every key and can modulate anywhere without retuning. This is what lets a guitar with fixed frets or a piano with fixed strings play in all keys. The trade-off is that intervals other than the octave are slightly detuned from the pure whole-number ratios of just intonation, so equal-tempered thirds and fifths are a few cents off their acoustically perfect versions, a compromise most listeners accept without noticing. Every note a chromatic tuner targets is calculated from a reference pitch using this formula. FretMind's tuner derives all its target frequencies from your chosen reference through equal temperament.