Note Frequency Chart
Note names, Hz and MIDI numbers C0–B8Runs locally · nothing uploaded
Preview sound
| Note | Frequency (Hz) | MIDI | Piano key | Wavelength (cm) |
|---|---|---|---|---|
| C4(Middle C) | 261.63 | 60 | 40 | 131.1 |
| C#4 | 277.18 | 61 | 41 | 123.75 |
| D4 | 293.66 | 62 | 42 | 116.8 |
| D#4 | 311.13 | 63 | 43 | 110.24 |
| E4 | 329.63 | 64 | 44 | 104.06 |
| F4 | 349.23 | 65 | 45 | 98.22 |
| F#4 | 369.99 | 66 | 46 | 92.7 |
| G4 | 392.00 | 67 | 47 | 87.5 |
| G#4 | 415.30 | 68 | 48 | 82.59 |
| A4 | 440.00 | 69 | 49 | 77.95 |
| A#4 | 466.16 | 70 | 50 | 73.58 |
| B4 | 493.88 | 71 | 51 | 69.45 |
Tap any row to hear it. Wavelength uses 343 m/s (air at 20 °C); piano key 1 is A0, the lowest key on an 88-key piano.
Frequency to note
Nearest note
C4
Offset
0 cents · 261.63 Hz
Also works as:note frequenciespiano key frequenciesmiddle C frequencyMIDI note numbersfrequency to note
How it works
Formula
f = A4 × 2^((MIDI − 69) ÷ 12)Equal temperament; A4 is MIDI 69, 440 Hz by default.
Piano key = MIDI − 20Wavelength (cm) = 34300 ÷ fWorked example
Given: Middle C (C4, MIDI 60), A4 = 440 Hz
- f = 440 × 2^(−9/12) ≈ 261.63 Hz.
- Piano key 40; wavelength ≈ 131.1 cm.
Result: Middle C ≈ 261.63 Hz.
Limitations
- Real pianos use stretch tuning, so extreme notes differ from theory by a few cents.
How to use
- 1Pick an octave, or All.
- 2Change the A4 reference if needed; the table updates.
- 3Tap a row to hear it, or enter a frequency below to find the nearest note.
FAQ
What frequency is middle C?
With A4 = 440 Hz, middle C (C4) is about 261.63 Hz—MIDI note 60 and key 40 on an 88-key piano.
How are note frequencies calculated?
In equal temperament each semitone multiplies the frequency by the 12th root of 2 (≈ 1.0595): f = 440 × 2^((MIDI − 69) / 12).
432 Hz vs 440 Hz?
440 Hz is the international standard. 432 Hz is about 32 cents lower; some prefer its sound, but there's no scientific evidence of special effects. Orchestras often tune slightly higher, like 442 Hz.
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