The A♯ Note
A♯ is a black key, immediately next to A. It sounds at 466.16 Hz in octave 4.
A♯ on the piano
Key facts
- On the keyboard
- a black key, immediately next to A.
- Frequency (octave 4)
- 466.16 Hz
- MIDI number (octave 4)
- 70
- Also written as
- B♭
- In key signatures
- The 5 sharp in the order of sharps.
A♯ and its enharmonic spellings
A♯ can also be written as B♭. These are enharmonic equivalents: the same pitch, the same key on the piano, a different name on the page. Which spelling is correct depends on the key and on how the note functions, not on the sound.
A♯ frequency in every octave
Frequencies for A♯ in scientific pitch notation, with A4 tuned to 440 Hz.
| Note | MIDI | Frequency |
|---|---|---|
| A♯1 | 34 | 58.27 Hz |
| A♯2 | 46 | 116.54 Hz |
| A♯3 | 58 | 233.08 Hz |
| A♯4 | 70 | 466.16 Hz |
| A♯5 | 82 | 932.33 Hz |
| A♯6 | 94 | 1864.66 Hz |
| A♯7 | 106 | 3729.31 Hz |
Chords on A♯
The most common chords built with A♯ as the root.
Scales starting on A♯
Keys and scales that use A♯ as their tonic.
All notes
常见问题
Where is A♯ on the piano?
A♯ is a black key, immediately next to A.
What frequency is A♯4?
A♯4 sounds at 466.16 Hz with A4 tuned to 440 Hz.
What is another name for A♯?
A♯ can also be written as B♭. They are the same pitch spelled differently.
