7-string and 8-string guitar tuning

Standard 7-string tuning adds a low B below the low E; standard 8-string adds a low F♯ below that. Exact pitches for both, and why the lowest strings are hard for tuners.

October 24, 2026

Extended-range guitars keep 6-string standard tuning exactly where it was and add strings below it. Everything you know above the low E still applies.

7-string standard: B E A D G B E

The low B sits a perfect fourth below the E, the same distance as most neighbouring strings, so the fifth-fret method extends to it: fret the seventh string at the fifth fret and it should match the open sixth string.

8-string standard: F♯ B E A D G B E

Again a perfect fourth: the eighth string at the fifth fret matches the open seventh.

Common variations

• Drop A on a 7-string: the low B dropped a whole step to A1, the 7-string version of drop D.
• Drop E on an 8-string: the low F♯ dropped a whole step to E1, an octave below the sixth string.
• Tuning the whole guitar down a half or whole step works exactly as it does on a 6-string; see half step down.

The low-string problem

At 46.25 Hz, the 8-string’s lowest note is below what a phone speaker can reproduce and close to the bottom of what a phone microphone hears well. The string’s overtones are much louder than the note itself, so a basic tuner hears the overtone an octave up (92.5 Hz) or a fifth above that and reports the wrong note. Turn the peg on that reading and you tighten a string that was already right.

Why tuners make octave errors on low strings explains the mechanism. In practice: pluck softly with the flesh of your thumb near the twelfth fret, where the fundamental is strongest, and choose the 7-string or 8-string tuning on the tuner so it knows which note it is looking for.