A standard modern piano has 88 keys.
This keyboard contains 52 white keys and 36 black keys, covering a tonal range of seven octaves plus a minor third. The lowest note is usually A0, while the highest is C8. This range became common as piano makers expanded the instrument during the 19th century.
Earlier pianos often had fewer keys because composers and performers did not yet require the extended range found in later Romantic-era music. Some modern keyboards and digital pianos deliberately use shorter layouts, such as 61 or 76 keys, for portability.
The number 88 describes the usual full-size piano, not every keyboard instrument sold as a piano. Concert grands, upright pianos, and many digital stage pianos follow this standard, although specialized historical and experimental instruments may differ.