Note to Hz (Frequency) Converter
Use this note to Hz converter to find the exact frequency of any musical note and octave 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 MIDI to Hz formula f = A4 × 2^((MIDI − 69) / 12) lets you compute any note from its MIDI number — for example, the middle C frequency (MIDI 60) works out to 261.63 Hz at the standard A4 = 440 Hz reference.
Enharmonic equivalents share the same frequency
In 12-TET, enharmonic equivalents — note pairs like C#4 and D♭4, or F#4 and G♭4 — are spelled differently but occupy exactly the same MIDI number and therefore produce the exact same frequency. For example, C#4 / D♭4 = MIDI 61 = 277.18 Hz at A4 = 440 Hz. This is unique to equal temperament; in just intonation and meantone temperaments, C# and D♭ were genuinely different pitches (the comma difference could be 20+ cents).
Cents: the fine-grained pitch unit
A cent is 1/100 of a semitone — or equivalently 1/1200 of an octave. It is the standard unit for describing tuning deviations and intonation errors. A well-trained ear can detect deviations as small as 5–10 cents. If you need to convert between a frequency ratio and cents, the formula is cents = 1200 × log₂(f₂/f₁). To check your tuning with a live microphone signal, the Hz to note converter shows the nearest note plus the offset in cents.
How notes map to frequency bands
The note frequency chart above shows how the pitch range spans the audio spectrum. 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. The interval calculator can show you the exact frequency ratio and cent distance between any two notes.