C Note Frequency in Every Octave
C runs from C0 at 16.35 Hz to C8 at 4186.0 Hz across the nine octaves of the chart, and each step up doubles the frequency. The one most people mean is middle C: C4, 261.63 Hz, MIDI note 60 and key 40 of an 88-key piano. The table below lists every C with the name it gets in scientific pitch notation and the name software in the Yamaha convention shows for the same key.
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C in all 9 octaves
Every C from C0 to C8 at A4 = 440 Hz. Each name links to the full page for that note, with its tuning references, harmonics and intervals. The last column is the label the same key gets in software that calls middle C by the name C3.
| Note | Hz | MIDI | Piano key | Yamaha name |
|---|---|---|---|---|
| C0 | 16.35 | 12 | off the piano | C-1 |
| C1 | 32.70 | 24 | 4 | C0 |
| C2 | 65.41 | 36 | 16 | C1 |
| C3 | 130.81 | 48 | 28 | C2 |
| C4Middle C | 261.63 | 60 | 40 | C3 |
| C5 | 523.25 | 72 | 52 | C4 |
| C6 | 1046.5 | 84 | 64 | C5 |
| C7 | 2093.0 | 96 | 76 | C6 |
| C8 | 4186.0 | 108 | 88 | C7 |
Moving up one row doubles the frequency and moving down halves it. The 88-key piano runs from A0 to C8, so rows marked off the piano can only be played electronically.
Which C is middle C?
Middle C is C4, the C nearest the middle of the piano keyboard, at 261.63 Hz when A4 is 440 Hz. The MIDI specification fixes it as note number 60, and on an 88-key piano it is key 40, counting from A0 at the far left. The C one octave below is C3 at 130.81 Hz and the C one octave above is C5 at 523.25 Hz.
An 88-key piano has 8 Cs, from C1 (key 4, 32.70 Hz) to C8 (key 88, 4186.0 Hz), the top key of the instrument. C0 is below the keyboard and only reachable with a synthesiser or the tone generator.
Why is C4 called C3 in some apps?
The MIDI specification fixes middle C as note number 60 but never says what to call the octave it sits in, so manufacturers picked different names for the same pitch. Scientific pitch notation, the convention this site uses, calls middle C by the name C4, and Roland chose the same labelling. Yamaha labelled note 60 as C3 instead, and plenty of DAWs and synths follow Yamaha. A few older programs call middle C by the name C5.
So C4 here, MIDI note 60 at 261.63 Hz, can read C3 on another screen. The pitch never changes, only the label: if your software shows every C one octave lower than the table above, it uses the Yamaha convention, and you convert by adding one to the octave number. When you need certainty, compare MIDI numbers or frequencies. The note frequency chart prints the MIDI number under every value for the same reason.
Which instruments have an open C string?
3 open strings in the TuneStand tuner registry are tuned to a C, from C2 up to C4.
Frequently asked questions
Which C is middle C?
Middle C is C4 in scientific pitch notation, 261.63 Hz at A4 = 440 Hz. It is MIDI note 60 and key 40 of an 88-key piano. Software that follows the Yamaha convention labels the same key C3.
Is middle C called C3 or C4?
Both names are in use for the same pitch. Scientific pitch notation, and Roland's documentation, call MIDI note 60 C4. Yamaha labelled it C3, and many DAWs and synths follow Yamaha. A few older programs call it C5. The frequency is 261.63 Hz whatever the label, so compare MIDI numbers when in doubt.
How many Cs are on a piano?
An 88-key piano has 8 Cs, from C1 at 32.70 Hz (key 4) to C8 at 4186.0 Hz (key 88), which is also the highest key. C0 at 16.35 Hz lies below the keyboard.
What is the frequency of C in every octave?
At A4 = 440 Hz: C0 16.35 Hz, C1 32.70 Hz, C2 65.41 Hz, C3 130.81 Hz, C4 261.63 Hz, C5 523.25 Hz, C6 1046.5 Hz, C7 2093.0 Hz, C8 4186.0 Hz. Each octave doubles the frequency of the one below.
Related notes and tools
Frequencies on this page are computed at build time from twelve tone equal temperament with A4 = 440 Hz, using the twelfth root of two (about 1.059463) per semitone. Nothing is typed in by hand. See the full method and sources. Maintained by FusionStudios. Last reviewed: .