Guitar Open C Tuner — Tune to Open C in Your Browser
Mic-based chromatic tuner pre-set to Open C. No download, no sign-up, works in your browser.
Tuning summary
- Notes (low to high)
- C2 · G2 · C3 · G3 · C4 · E4
- Instrument
- Guitar
- Difficulty
- Intermediate
- About this tuning
- Deep, resonant Open C — long the choice of John Martyn and Devin Townsend for big atmospheric rings.
Start tuning
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About Open C on guitar
Open C is CGCGCE, low to high. The open strings spell a C major chord, but spread differently than Open D or Open G — three Cs, two Gs, and a single high E give it a deep, almost piano-like voicing. The lowest note is C2, which is two whole steps below the standard E2, so the tuning feels heavier under the hand.
John Martyn and Devin Townsend are the most distinctive associated voices. Martyn's 'Solid Air' uses an Open C variant for its airy fingerpicking, and Townsend has built large parts of his progressive metal output around extended-range Open C. The tuning is a favourite for ambient and post-rock players because the wide intervals between open strings create a natural reverb-friendly chord wash.
Open C is harder on the strings than most open tunings — three of them go down significantly, but not symmetrically. Most players use a heavier 6th string (or even a baritone string) to compensate for the floppy low C. Without the right gauge the bottom string sounds loose and lifeless. With it, the tuning has a fundamentally different bass response from standard or Open G.
Beginner advice: start by learning the I (C, open), IV (F, fret 5 barre on the lowest five), and V (G, fret 7) chords. Suspended and add9 voicings are easy because the open strings already contain a fifth, and adding any moving note in the middle strings creates colour. If your guitar's low E string sounds dull when tuned to C, swap in a 13- or 14-gauge string for the bottom slot only.
Frequently asked questions
- Is Open C harder on a guitar than standard tuning?
- It puts less total tension on the neck than standard, which is gentle on the instrument, but the floppy low C string can buzz unless you use a heavier gauge.
- What artists use Open C?
- John Martyn, Devin Townsend, Jimmy Page (parts of 'Friends' and 'Bron-Y-Aur'), and many ambient fingerstyle players.
- Can I capo Open C?
- Yes — capoing transposes the whole tuning. A capo at fret 2 gives Open D, at fret 4 gives Open E.
- Do I need a different guitar for Open C?
- No, but you will likely want a heavier 6th string. A 13 or 14 instead of an 11 makes the low C sound clear instead of muddy.
- What is the difference between Open C and CGCGCE for cello-tuned guitar?
- They are the same set of pitches; CGCGCE is the explicit string spelling of Open C.