21.83Hz
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21.83 HzFrequency at A4 = 440 Hz
17MIDI note number
–Piano key (of 88)
15.71 mWavelength in air
About F0
F0 has a frequency of 21.83 Hz in standard tuning, where A4 is fixed at 440 Hz. It is MIDI note 17, outside the range of a standard piano.
In equal temperament every semitone multiplies the frequency by the twelfth root of two (≈1.05946), so F0 is 52 semitones below A4: f = 440 × 2^((17 − 69) / 12) = 21.83 Hz. The number in the name is the octave in scientific pitch notation, which starts each octave on C.
F0 frequency in different tunings
| Tuning reference | F0 frequency |
|---|---|
| A4 = 440 Hz (ISO 16 standard) | 21.83 Hz |
| A4 = 442 Hz (many European orchestras) | 21.93 Hz |
| A4 = 443 Hz (Berlin, Vienna) | 21.98 Hz |
| A4 = 435 Hz (French diapason normal, 1859) | 21.58 Hz |
| A4 = 432 Hz (alternative tuning) | 21.43 Hz |
| A4 = 415 Hz (Baroque pitch) | 20.59 Hz |
| C4 = 256 Hz (scientific pitch) | 21.36 Hz |
Intervals from F0
| Interval | Note | Frequency | Ratio (just) |
|---|---|---|---|
| Minor second | F♯0 | 23.12 Hz | 16:15 |
| Major second | G0 | 24.5 Hz | 9:8 |
| Minor third | G♯0 | 25.96 Hz | 6:5 |
| Major third | A0 | 27.5 Hz | 5:4 |
| Perfect fourth | A♯0 | 29.14 Hz | 4:3 |
| Tritone | B0 | 30.87 Hz | 45:32 |
| Perfect fifth | C1 | 32.7 Hz | 3:2 |
| Minor sixth | C♯1 | 34.65 Hz | 8:5 |
| Major sixth | D1 | 36.71 Hz | 5:3 |
| Minor seventh | D♯1 | 38.89 Hz | 9:5 |
| Major seventh | E1 | 41.2 Hz | 15:8 |
| Octave | F1 | 43.65 Hz | 2:1 |
Frequently asked questions
What is the frequency of F0?
F0 is 21.83 Hz when A4 = 440 Hz (21.43 Hz if A4 = 432 Hz).
What MIDI number is F0?
F0 is MIDI note number 17.
Is F0 on a piano?
No – a standard 88-key piano runs from A0 to C8, so F0 is outside its range.