This is a virtual piano with 88 keys tune to A440, showing the frequencies, in cycles per second (Hz), of each note (ie note frequencies of each note found on a standard piano). This distribution of frequencies is known as equal temperament, i.e. each successive pitch is derived by multiplying the previous by the twelfth root of two. For example, A4 is normally tuned to 440 Hz. To get the next semitone (A♯4), multiply 440 Hz by the twelfth root of two. To go from A4 to B4 (up two semitones), multiply 440 by the twelfth root of two squared. For other tuning schemes refer to Musical tuning.