Open A Tuning for Guitar

Open A runs E2, A2, E3, A3, C#4, E4, in playing order. The lowest-pitched string is E2 (82.41 Hz) and the highest is E4 (329.63 Hz), measured against A4 = 440 Hz. Those are the exact target frequencies the tuner on this page listens for.

3 of the 6 strings move: D3 up 2 semitone(s) to E3; G3 up 2 semitone(s) to A3; B3 up 2 semitone(s) to C#4. Work through them in order, then go back and re-check the first string — retuning shifts the neck tension slightly, so the earlier strings drift as you go.

The Open G interval pattern moved up a whole step, so material written in Open G transfers directly. Brighter and tighter than Open G, and common in blues where a slide part needs to sit higher without a capo.

E2 is 82.41 Hz at concert pitch (A4 = 440 Hz). That's the fundamental — the string also produces harmonics above it, which is why a tuner reading the wrong octave usually means it locked onto a harmonic rather than the fundamental. This is the lowest string in this guitar tuning.

The Open G interval pattern raised a whole step, spelling E, A, E, A, C#, E. Material written in Open G transfers directly by moving everything two frets. Like Open E, it is reached by tuning strings up rather than down — the second, third and fourth all rise — so it carries the same tension caveat and the same practical workaround of tuning to the lower relative and capoing. Where it earns its place is on instruments with a shorter scale, where the extra tension actually helps definition rather than threatening the neck.

Three strings go up a whole step. Tuning Open G and capoing at the second fret gets the same pitches with less tension.