43.65Hz
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43.65 HzFrequency at A4 = 440 Hz
29MIDI note number
9Piano key (of 88)
7.86 mWavelength in air
About F1
F1 has a frequency of 43.65 Hz in standard tuning, where A4 is fixed at 440 Hz. It is MIDI note 29 and key number 9 on an 88-key piano.
In equal temperament every semitone multiplies the frequency by the twelfth root of two (≈1.05946), so F1 is 40 semitones below A4: f = 440 × 2^((29 − 69) / 12) = 43.65 Hz. The number in the name is the octave in scientific pitch notation, which starts each octave on C.
F1 frequency in different tunings
| Tuning reference | F1 frequency |
|---|---|
| A4 = 440 Hz (ISO 16 standard) | 43.65 Hz |
| A4 = 442 Hz (many European orchestras) | 43.85 Hz |
| A4 = 443 Hz (Berlin, Vienna) | 43.95 Hz |
| A4 = 435 Hz (French diapason normal, 1859) | 43.16 Hz |
| A4 = 432 Hz (alternative tuning) | 42.86 Hz |
| A4 = 415 Hz (Baroque pitch) | 41.17 Hz |
| C4 = 256 Hz (scientific pitch) | 42.71 Hz |
Intervals from F1
| Interval | Note | Frequency | Ratio (just) |
|---|---|---|---|
| Minor second | F♯1 | 46.25 Hz | 16:15 |
| Major second | G1 | 49 Hz | 9:8 |
| Minor third | G♯1 | 51.91 Hz | 6:5 |
| Major third | A1 | 55 Hz | 5:4 |
| Perfect fourth | A♯1 | 58.27 Hz | 4:3 |
| Tritone | B1 | 61.74 Hz | 45:32 |
| Perfect fifth | C2 | 65.41 Hz | 3:2 |
| Minor sixth | C♯2 | 69.3 Hz | 8:5 |
| Major sixth | D2 | 73.42 Hz | 5:3 |
| Minor seventh | D♯2 | 77.78 Hz | 9:5 |
| Major seventh | E2 | 82.41 Hz | 15:8 |
| Octave | F2 | 87.31 Hz | 2:1 |
Instruments and voices that can play F1
Frequently asked questions
What is the frequency of F1?
F1 is 43.65 Hz when A4 = 440 Hz (42.86 Hz if A4 = 432 Hz).
What MIDI number is F1?
F1 is MIDI note number 29.
Is F1 on a piano?
Yes – it is key 9 of 88.