7-String Guitar Tuner
Tune a 7-string guitar to standard tuning BEADGBE with a free mic tuner showing note, Hz and cents for all seven strings.
Values use equal temperament with A4 fixed at 440 Hz. Play one open string at a time and match it against the tuner below.
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A 7-string guitar adds one extra low string below the standard six, tuned a fourth under the low E. That gives you B1, E2, A2, D3, G3, B3 and E4, the standard tuning used on most 7-string instruments in metal and progressive rock.
Tuning the extra low string
The top six strings of a 7-string guitar in standard tuning match a regular 6-string exactly: E2, A2, D3, G3, B3, E4. The seventh string sits a perfect fourth below the low E, landing on B1 at 61.74 Hz, a thick, low pitch that needs a heavier gauge string to stay in tune under normal tension.
Tune the extra string last, after the familiar six are settled, so you have a stable low E as a reference. Because B1 is well below where most guitar tuners are tested, take extra care that the microphone tuner is picking up the fundamental and not a harmonic; playing the string firmly and muting the rest helps.
Frequently asked questions
What is standard tuning for a 7-string guitar?
B1, E2, A2, D3, G3, B3, E4 from the lowest string to the highest. The top six strings match a standard 6-string guitar, with one extra B string added below the low E.
What frequency is the low B string?
B1 is 61.74 Hz in equal temperament with A4 at 440 Hz, noticeably lower than the 82.41 Hz low E of a standard 6-string guitar.
Do I need special strings for a 7-string guitar?
Yes, 7-string sets include a heavier gauge low B string designed to hold proper tension at that pitch. A standard 6-string low E will not sound right tuned down that far.