How to Tune a Guitar by Ear: The 5th-Fret Method

The short answer: Fret 5 on any string sounds the same note as the next (thinner) string played open — except the G string, where it's fret 4. Get one string in tune (from a piano, a tuning fork, or another instrument), then walk the pattern across the neck, matching each open string to the fretted note below it.

The pattern

Step by step:

1. Get the low E in tune from any reference.
2. Fret it at 5 (that's an A) — tune the open A string to match.
3. A string, fret 5 (D) → tune open D.
4. D string, fret 5 (G) → tune open G.
5. G string, fret 4 (B) → tune open B. ← the exception
6. B string, fret 5 (E) → tune open high E.

Why fret 4 on the G string?

Because the guitar's tuning isn't uniform: five of the gaps between strings are perfect fourths (5 frets), but G→B is a major third (4 frets). That kink exists to make chord shapes fit under human fingers, and it's the reason the B string feels weird in every scale shape you'll ever learn — not just in tuning.

Listening for "in tune": the wobble

Play the fretted note and the open string together. Out of tune, you'll hear a slow wah-wah-wah pulse — physicists call it beating, and it's the two sound waves drifting in and out of phase. As you tune closer, the wobble slows... and when it stops entirely, you're there. You're not judging pitch like a sommelier; you're listening for a pulse to flatline. Anyone can hear it.

The free ear training nobody notices

Tuning by ear five times a week is a compound-interest deposit into your ear: you're repeatedly asking "are these two pitches the same?", which is the foundational unit of all interval recognition. Players who've always leaned on a clip-on tuner skip those thousands of reps. Use the tuner for gigs (obviously); use your ear when nobody's waiting.

Two refinements when you're ready: match octaves instead of unisons (fret 5 on the low E is also the A string's note an octave down — octave shapes again), and try natural harmonics at frets 5 and 7, which ring longer and expose the beating more clearly.