The A Note

A is a white key on the piano. It sounds at 440 Hz in octave 4.

A on the piano

Press play to hear the note.

Key facts

On the keyboard
a white key on the piano.
Frequency (octave 4)
440 Hz
MIDI number (octave 4)
69
In key signatures
Never appears as an accidental in a key signature.

A frequency in every octave

Frequencies for A in scientific pitch notation, with A4 tuned to 440 Hz.

NoteMIDIFrequency
A13355 Hz
A245110 Hz
A357220 Hz
A469440 Hz
A581880 Hz
A6931760 Hz
A71053520 Hz

Chords on A

The most common chords built with A as the root.

See every A chord

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Scales starting on A

Keys and scales that use A as their tonic.

All notes

Frequently asked questions

Where is A on the piano?

A is a white key on the piano.

What frequency is A4?

A4 sounds at 440 Hz with A4 tuned to 440 Hz.