How many keys does a piano have?

Eighty-eight, on any full-size acoustic or digital piano. Upright or grand makes no difference. A concert grand and a battered school upright have the same 88 keys, in the same order, starting on the same note.

Smaller keyboards are a different story. A 61-key or 49-key controller is a shortened version of the same layout, not a different instrument. It simply stops earlier at both ends.

Fifty-two white and thirty-six black. The white keys are the notes A to G, repeated over and over. The black keys are the sharps and flats between them.

The black keys run in a repeating pattern: two, then three, then two, then three. That pattern is the most useful thing on the keyboard. It is how you know where you are without counting from the end. The white key just left of any group of two black keys is a C.

Seven full octaves plus three extra notes, usually written as seven and a quarter. The keyboard starts on A0, climbs through seven complete octaves, then adds A sharp, B and finally C8 at the top.

In sound, that is 27.5 Hz at the bottom to about 4,186 Hz at the top: from a rumble you feel as much as hear, up to a bright ping near the edge of what reads as a pitch.

It is where piano makers stopped, in the late 1800s. Early pianos had about 61 keys. Through the 1700s and 1800s makers kept adding notes, because composers kept writing past the end. Steinway settled on 88 in the 1880s and the rest followed.

It stopped there because the extra notes stop being useful. Below A0 the strings are so slack the ear struggles to hear a pitch; it reads as a growl. Above C8 the notes are so short and thin they are closer to a whistle than a tone.

A few. The Bösendorfer Imperial adds nine bass notes for 97 keys, coloured black so the player does not lose their bearings. Stuart & Sons in Australia has built pianos with 102 and even 108 keys. They are rare, expensive, and almost never required.

Fewer than you would think, to start.

• Most pop, rock and singer-songwriter music lives in about four octaves in the middle: roughly 49 keys’ worth.
• A 61-key keyboard covers nearly everything a beginner plays for a year or more, and it fits on a desk.
• The full 88 earns its keep for classical pieces, which run to both ends, and for weighted keys, which cheap short keyboards skip.

If you are choosing: 61 keys to find out whether you like it, 88 weighted keys once you know you do.

HitJam’s grand piano is the full 88, A0 to C8, recorded one note at a time from a real instrument. You can play it in this browser with no download and no account.

Your computer’s letter keys cover two octaves at a time. The left and right arrows move that window up and down the full 88, so you can reach every note. Plug in a MIDI keyboard and its own keys map straight onto the piano.