A typical piano has 88 keys spanning just over seven octaves. There are other, smaller keyboards or synthesizers that have fewer keys – most come in increments of 25, 32, 49, 61 or 72 keys.

An 88-key piano has seven octaves plus three lower notes (B, B flat and A) below the bottom C. It has 52 white keys and 36 black keys (sharps and flats), with each octave made up of seven white keys ...