Note Frequency Chart
Look up the frequency in hertz for every musical note from C0 to B8 using A4 = 440 Hz.
Common note frequencies
These four reference notes anchor the standard 88-key piano range and modern concert pitch.
Lowest piano key
A0
27.50 Hz
Middle C
C4
261.63 Hz
Concert pitch
A4
440.00 Hz
Highest piano key
C8
4186.01 Hz
Musical note frequency chart
Find a note name in the first column, then move across to its octave. Frequencies are rounded to two decimal places.
| Note | Octave 0 | Octave 1 | Octave 2 | Octave 3 | Octave 4 | Octave 5 | Octave 6 | Octave 7 | Octave 8 |
|---|---|---|---|---|---|---|---|---|---|
| C | 16.35 | 32.70 | 65.41 | 130.81 | 261.63 | 523.25 | 1046.50 | 2093.00 | 4186.01 |
| C♯ / D♭ | 17.32 | 34.65 | 69.30 | 138.59 | 277.18 | 554.37 | 1108.73 | 2217.46 | 4434.92 |
| D | 18.35 | 36.71 | 73.42 | 146.83 | 293.66 | 587.33 | 1174.66 | 2349.32 | 4698.64 |
| D♯ / E♭ | 19.45 | 38.89 | 77.78 | 155.56 | 311.13 | 622.25 | 1244.51 | 2489.02 | 4978.03 |
| E | 20.60 | 41.20 | 82.41 | 164.81 | 329.63 | 659.26 | 1318.51 | 2637.02 | 5274.04 |
| F | 21.83 | 43.65 | 87.31 | 174.61 | 349.23 | 698.46 | 1396.91 | 2793.83 | 5587.65 |
| F♯ / G♭ | 23.12 | 46.25 | 92.50 | 185.00 | 369.99 | 739.99 | 1479.98 | 2959.96 | 5919.91 |
| G | 24.50 | 49.00 | 98.00 | 196.00 | 392.00 | 783.99 | 1567.98 | 3135.96 | 6271.93 |
| G♯ / A♭ | 25.96 | 51.91 | 103.83 | 207.65 | 415.30 | 830.61 | 1661.22 | 3322.44 | 6644.88 |
| A | 27.50 | 55.00 | 110.00 | 220.00 | 440.00 | 880.00 | 1760.00 | 3520.00 | 7040.00 |
| A♯ / B♭ | 29.14 | 58.27 | 116.54 | 233.08 | 466.16 | 932.33 | 1864.66 | 3729.31 | 7458.62 |
| B | 30.87 | 61.74 | 123.47 | 246.94 | 493.88 | 987.77 | 1975.53 | 3951.07 | 7902.13 |
Chart standard: 12-tone equal temperament, A4 = 440 Hz. The live detector is optimized for approximately 50–1,200 Hz; the full chart remains useful as a reference beyond that detection range.
How to use this chart
- Identify the note and octave you want, such as C4 or A4.
- Read the intersecting cell to find its frequency in hertz.
- Play or sing the pitch and use the online pitch detector to compare the detected note and frequency.
- Adjust the sound until the measured frequency approaches the chart value.
Note frequency formula
Equal temperament divides every octave into 12 equal semitones. A note's frequency is:
f = 440 × 2(n − 69) / 12
In this formula, n is the note's MIDI number and 69 is A4. Moving up one octave doubles the frequency; moving down one octave halves it.
Note frequency questions
What frequency is middle C?
Middle C, written C4 in scientific pitch notation, is approximately 261.63 Hz when A4 is tuned to 440 Hz.
Why is A4 equal to 440 Hz?
A4 = 440 Hz is the most widely used modern concert-pitch reference. Assigning A4 to 440 Hz gives every other note in equal temperament a repeatable calculated frequency.
Do sharps and flats have the same frequency?
In 12-tone equal temperament, enharmonic notes such as C sharp and D flat use the same frequency. Other tuning systems can give those spellings slightly different pitches.
How are musical note frequencies calculated?
Each semitone is one twelfth of an octave. Starting from A4 at 440 Hz, multiply by two raised to the number of semitones from A4 divided by 12.
Does changing the A4 reference change the chart?
Yes. An A4 reference such as 442 Hz or 432 Hz shifts every frequency proportionally. This chart uses the standard A4 = 440 Hz reference.
Check a live note
Use your microphone to identify a note, frequency, and tuning offset.
Open the pitch detector