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Open chord tuning · C major

Open C guitar tuning: C G C G C E

Tune the open strings to C2, G2, C3, G3, C4 and E4 so the unfretted guitar creates a wide C-major chord with repeated C and G notes.

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Live target±5 cents
C2G2C3G3C4E4
FlatIn tuneSharp
01Exact C2 G2 C3 G3 C4 E4 targets
02Three C targets with exact string selection
03Open-chord note and frequency table
Know the target

A resonant C-major chord across six open strings

Open C places C in three octaves and G in two, with the high E providing the major third. The broad unison-and-octave layout is popular for resonant fingerstyle, slide and altered chord voicings because the open strings keep ringing around a C foundation.

This tuning changes four strings from E Standard while G3 and E4 remain in place. Tune low to high and use small adjustments around the repeated C targets, selecting the exact string or peg when the same note appears elsewhere on the guitar.

Four clear steps

How to tune accurately

  1. 1Select the low C2 target and lower the sixth string gradually from E2.
  2. 2Continue through G2, C3 and the unchanged G3 while muting strings that are ringing.
  3. 3Raise B3 carefully to C4, then verify the high E4 string remains in tune.
  4. 4Strum the open C-major voicing and make a second pass through all six strings.
Reference: A4 = 440 Hz

Notes and frequencies

Physical stringTargetFrequency
String 6 C2 65.41 Hz
String 5 G2 98.00 Hz
String 4 C3 130.81 Hz
String 3 G3 196.00 Hz
String 2 C4 261.63 Hz
String 1 E4 329.63 Hz

Changing the tuner calibration recalculates every target from A4 = 415–450 Hz. The values above use the common 440 Hz reference.

Practical answers

Frequently asked questions

What notes are Open C tuning?

From low to high, Open C is C2, G2, C3, G3, C4 and E4.

Is Open C the same as C Standard?

No. Open C creates a C-major chord on the open strings, while C Standard lowers every string by the same interval and preserves Standard-tuning relationships.

Does tuner.love upload my microphone audio?

No. Pitch analysis runs locally in your browser. Microphone audio is not uploaded to a backend and is never replayed through your speakers.

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Open chord tuning · E major · Higher tensionOpen E guitar tuning: E B E G♯ B EOpen guide →Open chord tuning · A majorOpen A guitar tuning: E A C♯ E A EOpen guide →Open chord tuning · D minorOpen D minor guitar tuning: D A D F A DOpen guide →6-string guitar · 29 tuningsFree online guitar tuner for E Standard, drop and open tuningsOpen guide →
Open chord tuning · C major

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Open open c guitar tuning: c g c g c e