Free Online 12-String Guitar Tuner
Six courses, ten pitches. Each string read against the right one.
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Six courses, left to right: 6th (the thickest pair) to 1st. Tune each string of a pair on its own with its partner damped.
Allow microphone access to begin
How to use this tuner
Click Start Tuning and allow microphone access. Play one string of a course at a time, damping its partner with a spare finger, and the tuner reads it against whichever of the course’s pitches is nearer. Tap a course button to hear its main pitch and lock the tuner to that course.
The bar spans −50 to +50 cents. Zero is perfectly in tune. In string mode the value is the distance to the target string, not to the nearest chromatic note, so a string that is a long way off pins the needle at the edge until you get close.
The tuner reads against the nearest open string of 12-string standard tuning (E2, A2, D3, G3, B3, E4), so the cents value is the distance to that string, not to the nearest chromatic note. Tap a string to hear its reference pitch and lock the tuner to it; tap again to release.
Guitar is already selected and no transposition is applied: guitar is written an octave above where it sounds, and the tuner shows the sounding octave. Changing the dropdown to another instrument turns string mode off; tapping a string turns it back on.
Default is A440. Tap + / − to match a recording or another instrument that cannot be adjusted.
A 12-string guitar in standard tuning has six courses tuned E2, A2, D3, G3, B3, E4, exactly like a six-string, with a second string on each course. On the four lowest courses that second string is tuned an octave higher: E3, A3, D4, G4. On the B and high E courses it is tuned in unison. That makes ten distinct pitches across twelve strings, and it is why a chromatic tuner reads a correctly tuned 12-string as a mess of alternating notes. Each button above the display shows a course with both its pitches, and the tuner accepts either one for that course.
Tune one string at a time. Rest a fingertip on the other string of the course so only one sounds, tune it to zero, then swap and do its partner. Two strings that each read zero are in tune with each other; two strings tuned to each other by ear can share the same error. Take the low course first and work up, then go round again: a 12-string carries roughly twice the tension of a 6-string, and changing one course visibly moves the pitch of the others as the neck and top respond. Three passes on a fresh set is not unusual. Tune up to pitch from below on every string so the peg is loaded in the direction that holds.
The octave strings are the thin ones, and the octave G, G4, is the thinnest string on the instrument and the one most likely to break while tuning. Turn its peg in small moves and stop as soon as the tuner reaches zero. Many players tune their 12-string a whole step down, D standard, or a half step down, to reduce the tension and the strain on the neck and the fingers, and then capo to reach concert pitch; the chromatic tuner handles those, and the octave logic is the same, each pair a semitone or two lower.
The characteristic shimmer of a 12-string comes from the pairs being very slightly out of tune with each other, not from being perfectly matched, so do not chase the last cent on the octave strings if the instrument sounds right. What you are listening for is a slow, even beating on a sustained chord; fast beating means a pair is genuinely out. Intonation is harder on a 12-string because the thin octave strings and their heavy partners need different saddle compensation; if open strings read zero and twelfth-fret notes on the octave strings read sharp, that is the saddle, not the tuning.
Frequently asked questions
How is a 12-string guitar tuned?
The six courses are E2, A2, D3, G3, B3, E4, like a six-string. The E, A, D, and G courses each have a second string an octave higher (E3, A3, D4, G4); the B and high E courses have a second string in unison.
Which string in a pair should I tune first?
It does not matter, as long as you tune each string on its own with the other damped. Tune every string to the tuner rather than to its partner, so both strings of a course are checked against the same reference.
Should a 12-string be tuned down?
Many players tune a whole step or a half step down to reduce the high tension, and capo up if they need concert pitch. Vintage and lightly built 12-strings often should be. Use the chromatic tuner for a lowered set; the octave relationships are unchanged.
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