Press Play for the low C, then each string below: C G C G C E, a C major chord.
Open C Tuning: 65.41 Hz sawtooth tone
Start with your device volume low.
Sawtooth wave · both channels
65.41Hz
Period 15.3 ms
Wavelength 5.24 m (17.2 ft)
The note C2
Ready. It starts quiet and fades in over half a second.
A steady tone can harm ears and speakers before it sounds loud. Hear nothing? Do not turn it up to find the tone: small speakers cannot play very low tones, and many adults cannot hear very high ones.
Percent of this tool's loudest. Your device volume does the rest.
6th string C2, down two whole steps65.41 Hz, four semitones under the low E of standard tuning (82.41 Hz): the furthest any string moves here. Held at fret 7 it sounds the 5th string's G.
5th string G2, the chord's fifth98 Hz, two semitones under standard's A (110 Hz) and one octave under the 3rd string. Held at fret 5 it sounds the 4th string's C.
4th string C3, down a whole step130.81 Hz, two semitones under standard's D (146.83 Hz): the second of the three Cs, an octave over the 6th string. Held at fret 7 it sounds the 3rd string's G.
3rd string G3, left as it is196 Hz. Not retuned, so it is the note to trust: the 5th string is set one octave under it. Held at fret 5 it sounds the 2nd string's C.
2nd string C4, up a half step261.63 Hz, middle C: one semitone over standard's B (246.94 Hz). Held at fret 4 it sounds the 1st string's E.
1st string E4, left as it is329.63 Hz. Not retuned, and the only E of the six: the major third that makes the open chord C major and not a bare C and G.
How it works
Open C tuning is C G C G C E, low to high (CGCGCE). From standard the sixth string drops two whole steps, the fifth and fourth drop one, and the second rises a half step.
Read the full guide
How to tune a guitar to open C
1. Start in standard tuning. The third and first strings, G and E, do not move.
2. Press Play: the sixth string's C sounds. Lower your low E all the way to it.
3. Press the fifth and fourth string rows and lower A to G, then D to C.
4. Press 2nd string C4, up a half step and raise the B string to it. It is the only string you tighten.
5. Hold any of the three thickest strings at fret 12. It should sound the open string two places higher, because C G C repeats one octave up.
Small speakers cannot produce 65.41 Hz itself. Each tone is a sawtooth wave, so the low C is heard from its overtones.
Questions and answers
What is open C tuning?
A guitar tuning whose open strings hold only the notes of a C major chord: C, E and G. One finger across all six strings moves the chord up the neck: fret 5 gives F major and fret 7 gives G major.
Is CGCGCE tuning the only open C?
No. C E G C E G repeats the three notes of the chord, and C C G C E G follows the overtones of the note C. CGCGCE is the form this page plays.
Is open C guitar tuning the same as drop C?
Only on the three thickest strings, C G C in both. Drop C goes on F A D, standard's shape a whole step down. Open C goes on G C E, so every open string belongs to the chord.