Open C Tuning on 6-string guitar
Open C tuning is C2 G2 C3 G3 C4 E4, written CGCGCE. Lower the 6th two whole steps to C2, the 5th a whole step to G2, the 4th a whole step to C3, raise the 2nd a semitone to C4, and lower the 1st a whole step to E4. Only the 3rd string keeps its standard G3.
| String | Note | Frequency (Hz) | MIDI |
|---|---|---|---|
| 6th (lowest) | C2 | 65.41 | 36 |
| 5th | G2 | 98.00 | 43 |
| 4th | C3 | 130.81 | 48 |
| 3rd | G3 | 196.00 | 55 |
| 2nd | C4 | 261.63 | 60 |
| 1st (highest) | E4 | 329.63 | 64 |
Every frequency is computed from the MIDI number, not typed in. Each one links to its own reference page.
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Why guitarists use Open C tuning
Four of the six strings sound the root or the fifth, which produces a much deeper and more resonant open chord than open G or open D. It is also the most disruptive common tuning to reach from standard, which is why players tend to keep a second guitar in it.
Where you will hear it: fingerstyle, folk, acoustic instrumental. That list is deliberately limited to genres and playing traditions. Attributing a tuning to specific songs or players is the kind of claim that needs a source, and this page does not make claims it cannot back up.
Open C compared with standard EADGBE tuning
This is the table that tells you how far to turn each peg, in semitones and in hertz. A negative semitone value means the string goes down.
| String | Standard | Standard (Hz) | Open C | Open C (Hz) | Change |
|---|---|---|---|---|---|
| 6th (lowest) | E2 | 82.41 | C2 | 65.41 | -4 semitones (-17.00 Hz) |
| 5th | A2 | 110.00 | G2 | 98.00 | -2 semitones (-12.00 Hz) |
| 4th | D3 | 146.83 | C3 | 130.81 | -2 semitones (-16.02 Hz) |
| 3rd | G3 | 196.00 | G3 | 196.00 | unchanged |
| 2nd | B3 | 246.94 | C4 | 261.63 | +1 semitone (+14.68 Hz) |
| 1st (highest) | E4 | 329.63 | E4 | 329.63 | unchanged |
Notice that equal semitone steps are not equal hertz steps: the same whole step is worth about 9 Hz down at the bottom string and far more at the top. That is why tuners report cents, which are proportional, rather than hertz.
How to tune to Open C, string by string
- Play the 6th (lowest) open and adjust until the tuner reads C2 at 65.41 Hz. Aim to land inside five cents.
- Play the 5th open and adjust until the tuner reads G2 at 98.00 Hz. Aim to land inside five cents.
- Play the 4th open and adjust until the tuner reads C3 at 130.81 Hz. Aim to land inside five cents.
- Play the 3rd open and adjust until the tuner reads G3 at 196.00 Hz. Aim to land inside five cents.
- Play the 2nd open and adjust until the tuner reads C4 at 261.63 Hz. Aim to land inside five cents.
- Play the 1st (highest) open and adjust until the tuner reads E4 at 329.63 Hz. Aim to land inside five cents.
Retune in two passes. Changing the tension on one string changes the pull on the neck, so the strings you set first will have drifted slightly by the time you finish the last one. That effect is larger the further the tuning sits from standard, so a tuning that moves four or more strings almost always needs a third pass.
Frequently asked questions
What notes is Open C tuning on a 6-string guitar?
Open C is C2, G2, C3, G3, C4, E4, written CGCGCE. Lower the 6th two whole steps to C2, the 5th a whole step to G2, the 4th a whole step to C3, raise the 2nd a semitone to C4, and lower the 1st a whole step to E4. Only the 3rd string keeps its standard G3.
What are the frequencies of Open C tuning?
C2 is 65.41 Hz, G2 is 98.00 Hz, C3 is 130.81 Hz, G3 is 196.00 Hz, C4 is 261.63 Hz, E4 is 329.63 Hz, all in twelve tone equal temperament with A4 at 440 Hz.
How many strings change compared to standard tuning?
4 of 6. the 6th (lowest) goes from E2 to C2 (down 4 semitones), the 5th goes from A2 to G2 (down 2 semitones), the 4th goes from D3 to C3 (down 2 semitones), the 2nd goes from B3 to C4 (up 1 semitone).
What is the lowest note in Open C tuning?
C2 at 65.41 Hz, MIDI note 36. Low notes take longer for a pitch detector to lock onto, so play the string firmly and let it ring before trusting the cents reading.
Other 6-string guitar tunings
More tuning references
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: .