Note to Hz (Frequency) Converter
Convert any musical note and octave to its exact frequency in Hz using 12-tone equal temperament. Adjustable A4 reference tuning (380–480 Hz), audio playback, MIDI number, wavelength, and a full note-frequency reference table.
Input
Result
Note & Frequency Reference (A4 = 440 Hz)
| Octave | C (Hz) | A (Hz) | MIDI Range | Notable Notes |
|---|---|---|---|---|
| 0 | 16.352 | 27.500 | 12 – 23 | A0 = lowest piano note (27.5 Hz). Below most speech and music. |
| 1 | 32.703 | 55.000 | 24 – 35 | Pedal C (32.7 Hz). Bass guitar low E is E1 = 41.2 Hz. |
| 2 | 65.406 | 110.000 | 36 – 47 | Bass guitar mid range. Cello low C = C2 = 65.4 Hz. |
| 3 | 130.813 | 220.000 | 48 – 59 | Guitar low E = E2 (82.4 Hz, octave 2). Tenor voice range. |
| 4 | 261.626 | 440.000 | 60 – 71 | Middle C (C4) = 261.63 Hz. Concert A4 = 440 Hz. |
| 5 | 523.251 | 880.000 | 72 – 83 | Soprano upper range. High soprano C = C5. |
| 6 | 1,046.502 | 1,760.000 | 84 – 95 | Violin upper range, "whistle register" in human voice. |
| 7 | 2,093.005 | 3,520.000 | 96 – 107 | Past most acoustic instruments. Piccolo top notes. |
| 8 | 4,186.009 | 7,040.000 | 108 – 119 | C8 = highest piano note (4,186 Hz). Mostly synthesizer territory. |
About Notes, Frequencies & A4 Reference
Western music uses 12-tone equal temperament (12-TET): every octave is divided into 12 equally-spaced semitones, where each semitone is the 12th root of 2 times the frequency of the previous one (a ratio of ~1.0595). Doubling the frequency moves up exactly one octave; halving it moves down one.
A4 = 440 Hz as the modern standard
The concert pitch A4 = 440 Hz was standardised by ISO 16:1975. Almost all modern orchestras and recorded music tune to this reference. Some orchestras still use A4 = 442 or 443 Hz for a slightly brighter sound. Historical "baroque pitch" was around A4 = 415 Hz — roughly a semitone below modern pitch.
The MIDI number system
MIDI assigns each note an integer: Middle C (C4) = 60, A4 = 69, the lowest piano note A0 = 21, the highest piano note C8 = 108. The full MIDI range is 0 (C-1, ~8.18 Hz) to 127 (G9, ~12,544 Hz). The frequency formula f = A4 × 2^((MIDI − 69) / 12) lets you compute any note from its MIDI number.
How notes map to frequency bands
Roughly: sub-bass (below 60 Hz) covers C0–B1, bass (60–250 Hz) covers C2–B3, midrange (250 Hz–2 kHz) covers most musical content C4–B6, presence/brilliance (2–20 kHz) handles harmonics, sibilance, and "air" — that's why upper octaves matter even though we don't sing in them.