About Open C tuning
Open C tunes the guitar to a wide, deep C major chord with the sixth string down two full steps to C. The result is huge — nearly a piano's worth of low-end resonance — which is why it turns up everywhere from Led Zeppelin's acoustic side to Devin Townsend's wall of sound.
From standard: sixth E→C (down 2 steps), fifth A→G, fourth D→C (down a step each), third G stays, second B→C (up a half step), first E stays.
Open C tuning notes & frequencies (A4 = 440 Hz)
| String | Note | Frequency |
|---|---|---|
| 6 | C2 | 65.41 Hz |
| 5 | G2 | 98.00 Hz |
| 4 | C3 | 130.81 Hz |
| 3 | G3 | 196.00 Hz |
| 2 | C4 | 261.63 Hz |
| 1 | E4 | 329.63 Hz |
How to tune to Open C from standard
- String 6 (E2): tune down 4 semitones to C2.
- String 5 (A2): tune down a whole step to G2.
- String 4 (D3): tune down a whole step to C3.
- String 2 (B3): tune up a half step to C4.
After changing string tension this much, make a second tuning pass — the neck settles slightly and the first strings you tuned will have drifted.
Songs & artists in Open C
- Friends — Led Zeppelin
Devin Townsend and John Butler are famous modern residents of Open C.
String gauge advice
A heavier sixth string (.052+) keeps the low C from flapping.
FAQ
What are the notes of Open C tuning on guitar?
Open C tuning is C2, G2, C3, G3, C4, E4 from the lowest string to the highest.
How do I tune my guitar to Open C?
Starting from standard tuning: String 6 (E2): tune down 4 semitones to C2. String 5 (A2): tune down a whole step to G2. String 4 (D3): tune down a whole step to C3. String 2 (B3): tune up a half step to C4. Use the tuner above — it highlights the string it hears and shows exactly how many cents you are from the target.
Is this tuner free and private?
Yes — no ads, no signup, and all audio is processed locally in your browser. Nothing is recorded or uploaded.
Embed this tuner
Add the Open C tuner to your own site or blog post with an iframe:
<iframe src="https://tunewell.net/embed/guitar/open-c" width="420" height="560" style="border:0" title="Open C Guitar Tuner"></iframe>