Piano Keyboard: 88 Keys

The standard piano keyboard contains 88 keys. Since the musical alphabet contains only seven (7) letters, each letter occurs 7 or 8 times. The distance between each repetition of any letter is one octave. The image below labels the octaves on the piano keyboard. The lowest pitches have low octave numbers (0, 1, etc.), while the highest pitches have high octave numbers (7, 8, etc.).