Piano notes: the name of every key

Piano notes are named with seven letters, A, B, C, D, E, F and G, for the white keys, and with sharps and flats for the black keys. Those 12 names repeat in every octave, and a number after the letter says which octave a key is in. C4 is middle C, A4 is the A used as the standard tuning pitch (440 Hz), and an 88-key piano runs from A0 to C8. The chart at the end of this page lists all 88 keys with their names, colors and frequencies.

On the keyboard above, the lit keys are the four Cs from C3 to C6: the same letter in four octaves. The second of them, C4, is middle C. The labeled diagram on this page shows one full octave, from C4 to B4, with both names on every black key.

The musical alphabet: A to G

Music uses only seven letters. After G the alphabet starts again at A, one octave higher. On the piano those seven letters belong to the white keys, and because teaching usually starts from C, one octave of white keys is read C, D, E, F, G, A, B. Played from one C to the next, those white keys form the C major scale; piano scales on our companion site shows how the other scales are built.

Many countries use syllables instead of letters. In fixed-do solfège, C is always Do, so C D E F G A B becomes Do Re Mi Fa Sol La Si. In the movable-do system common in American classrooms, Do is the first note of whatever key a song is in, and the seventh note is usually sung Ti.

Sharps, flats and the black keys

Each black key takes its name from a white neighbor. A sharp (#) raises a note by a half step, the smallest step on the keyboard, and a flat (b) lowers it by a half step. The black key just right of C is C sharp (C#); seen from D, the same key is D flat (Db). So every black key has two names:

Printed music uses the symbols ♯ and ♭; this site writes them as # and b.

Enharmonic notes: one key, two names

Two names for the same key are called enharmonic equivalents. C# and Db are the familiar example, but white keys have them too. Because E and F are only a half step apart, E# is another name for F and Fb is another name for E; likewise, B# is C and Cb is B. The octave number follows the letter, so B#3 is the same key as C4 and Cb4 is the same key as B3. Which name a piece uses depends on its key signature and harmony, not on the sound: on a piano, C# and Db are one key and sound identical.

Octave numbers and middle C

The numbers come from scientific pitch notation. Each octave starts on C, so the number goes up by one at every C: the key after B3 is C4. On an 88-key piano, octave 0 has only three keys (A0, A#0/Bb0 and B0), octaves 1 through 7 have all 12, and octave 8 has a single key, C8. That makes eight each of A, A#/Bb, B and C, and seven of every other note.

Middle C is C4: key 40, the fourth C from the left, sounding at about 261.63 Hz. It sits a little left of the physical center of an 88-key piano, which falls between E4 and F4. Some music software labels middle C as C3 instead; the key and its pitch are the same, and only the number differs. In MIDI, the data format keyboards use to talk to computers, middle C is note number 60.

How to find any note fast

You never need to count up from the bottom key. Use the black-key groups as landmarks:

1. Find a group of two black keys. The white key just left of it is C, the key between the two black keys is D, and the key just right of the group is E.
2. Find a group of three black keys. The white key just left of it is F; G and A sit between the black keys, and B is just right of the group.
3. Name a black key from either neighbor: a sharp of the white key to its left, or a flat of the white key to its right.
4. Add the octave number. Count the Cs from the left end of an 88-key piano (C1, C2, C3 and so on), or start at middle C and count Cs up or down.
5. Test yourself: set the labels on the keyboard above to None, name a key, then switch back to note names to check.

The keyboard layout guide shows the whole pattern at once, including where each keyboard size starts and ends.

How the frequencies work

A note's pitch is its frequency, measured in hertz (Hz), or vibrations per second. Modern pianos use equal temperament, which splits every octave into 12 equal half steps. Each key is the twelfth root of two, about 1.059463, times the frequency of the key below it, so 12 half steps exactly double the frequency. That is why A3, A4 and A5 are 220, 440 and 880 Hz.

With A4 as key 49, the frequency of key number n is f = 440 × 2^((n − 49) / 12). The chart below applies that formula to every key and rounds to two decimals. Real acoustic pianos are tuned with slightly stretched octaves, so their highest and lowest notes can sit a little away from these theoretical values. To hear any of these notes, play them on the full 88-key online piano.

All 88 piano keys with names and frequencies

Key 1 is the lowest key, A0, and key 88 is the highest, C8. Middle C is key 40 and A4 (440 Hz) is key 49. Black keys are listed with both names.