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How to Tune a Guitar (Standard & Alternate)
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About this reference
From the music-learning collection, adapted for Philojain Music Muse. Referenced sources remain credited in the article.
Playing & Technique · Guide
Standard tuning is E–A–D–G–B–E, low string to high, each string a perfect fourth above the last except G to B, which is a major third. Two reliable methods get you there — tuning by ear off a reference string, or trusting an electronic tuner — and a handful of alternate tunings open up sounds standard tuning can't reach easily.
01 — The Reference
Six strings, six fixed frequencies.
These are the equal-tempered frequencies relative to the international pitch standard, A4 = 440 Hz.1
| 6th (thickest) | E2 | 82.41 Hz |
| 5th | A2 | 110.00 Hz |
| 4th | D3 | 146.83 Hz |
| 3rd | G3 | 196.00 Hz |
| 2nd | B3 | 246.94 Hz |
| 1st (thinnest) | E4 | 329.63 Hz |
Method: each semitone in equal temperament multiplies frequency by the 12th root of 2; adjacent strings sit a perfect fourth apart (5 semitones) except G to B, a major third (4 semitones).2
02 — Method
Two ways to get there.
By ear — the 5th-fret relative method
- Set the reference. Tune the low E string (6th, thickest) to a piano, tuning fork, app or another in-tune guitar — everything else is tuned relative to this string.
- Press the 5th fret of the low E string. That note is A — tune the open 5th string (A) to match it.
- Press the 5th fret of the A string. That note is D — tune the open 4th string (D) to match it.
- Press the 5th fret of the D string. That note is G — tune the open 3rd string (G) to match it.
- Press the 4th fret (not the 5th) of the G string. That note is B — tune the open 2nd string (B) to match it. This is the one exception, because G to B is a major third, not a perfect fourth.
- Press the 5th fret of the B string. That note is E — tune the open 1st string (high E) to match it.
By electronic tuner
- Pick the string, one at a time.
- Read the display — clip tuners sense vibration through the guitar itself; pedal and app tuners listen through a microphone.
- Tune up to pitch rather than down, to keep even tension on the string as it settles.
- Re-check the low E string after tuning all six — bringing later strings up to pitch can pull the neck slightly and shift the earlier ones.
03 — Alternate Tunings
When standard isn’t the whole story.
Alternate tunings change what's easy to play and how the open strings ring — not what's "correct." Notes listed low string to high string.
| Standard | E A D G B E | Reference tuning |
| Half step down | E♭ A♭ D♭ G♭ B♭ E♭ | Everything down one semitone; easier bends, different feel |
| Drop D | D A D G B E | Low string dropped a whole step; deeper root notes4 |
| Double Drop D | D A D G B D | Drop D plus the high E also dropped to D |
| Open D | D A D F♯ A D | Sounds a D major chord open; common in slide playing3 |
| Open G | D G D G B D | Sounds a G major chord open; common in slide and blues3 |
| Open E | E B E G♯ B E | Sounds an E major chord open3 |
| DADGAD | D A D G A D | Open, suspended sound (no 3rd); folk and Celtic playing3 |
| Drop C | C G C F A D | Standard tuned down a step, then dropped further; heavier styles3 |
Method: standard-derived tunings (half step down, Drop D, Double Drop D) follow directly from the reference frequencies in Section 01; open and modal tunings are cross-checked against the sources below.
Deeper — What In Tune Is Targeting
What “in tune” is actually targeting
Both methods in Section 02 point at the same target, worth naming directly: equal temperament, the tuning system nearly every guitar, piano and tuner in wide use is built around. Per Britannica, equal temperament “divides the octave into 12 equal semitones” and “enables keyboard instruments to play in all keys with minimal flaws in intonation” — the same 12-equal-step arithmetic Section 01's frequency table above is built from. Britannica also states that equal temperament “replaced earlier tuning systems that were based on acoustically pure intervals,” which is the detail worth sitting with: today's standard tuning is a deliberate, useful compromise, not a “perfect” one.
That's why a careful by-ear tuning and a careful electronic tuning reading should agree closely — both are aiming at the identical equal-tempered target, not two competing standards — and it's also why even a perfectly executed tuning can still leave some chords sounding very slightly less pure than others. That's the compromise equal temperament was built to make, playing in every key at the cost of no single key sounding acoustically perfect, not a sign anything was done wrong at the tuning peg.
Deeper — The Same Compromise, Everywhere
The same compromise, in every alternate tuning above
Nothing in Section 03's alternate-tunings table opts out of this — Drop D, the open tunings and everything else in that list simply reassigns which equal-tempered pitches the open strings sound, using the identical 12-semitone grid. Retuning the guitar changes which chords fall easily under open strings; it doesn't trade equal temperament's compromise for a purer one.
Worth separating from the FAQ above, too: “why do guitars go out of tune” (temperature, humidity, string stretch — Section 04's answer) is a completely different question from the one this section answers. String drift is a mechanical problem that a fresh tuning fixes outright. Equal temperament's small, permanent trade-off is not a problem a more careful tuning session can ever fix — it's the designed cost of one grid working across every key, present even in a guitar tuned as precisely as physically possible.
04 — Common Questions
Asked at the tuning peg.
Why do guitars go out of tune?
Strings stretch and settle, temperature and humidity change the wood and string tension, and normal playing works the string over the frets and nut — a small drift is normal and not a sign anything is wrong.
What is A440 and why does it matter?
A440 is the agreed reference pitch — the note A above middle C set at 440 Hz. It was recommended internationally in 1939 and adopted as ISO 16 in 1955, which is why tuners, pianos and orchestras worldwide tune to the same pitch.
Is it fine to tune with a phone app instead of a real tuner?
For most practice and home use, yes — a decent tuner app reads pitch accurately through the phone's mic. In a noisy room or for stage use, a clip-on tuner, which senses vibration through the guitar itself, is more reliable.
What's the easiest alternate tuning to start with?
Drop D — only one string changes from standard, so the chord shapes you already know mostly still work, and the deeper low string is an easy, obvious difference to hear.
Can I damage my guitar by tuning too high?
Yes, if you tune well above pitch — excess string tension can, in extreme cases, damage the neck or bridge. Tuning down to a lower alternate tuning is generally safe; when in doubt, tune up slowly and stop the moment you reach the note, rather than overshooting and pulling back down.
05 — Sources
Where these facts come from
- Wikipedia — “A440 (pitch standard)”en.wikipedia.org · accessed 25 Jul 2026
- Seventh String Software — “Note Frequencies”seventhstring.com · accessed 25 Jul 2026
- Acoustic Guitar — “DADGAD, Dropped D, Open G, and More! A Beginner’s Guide to Alternate Tunings”acousticguitar.com · accessed 25 Jul 2026
- Wikipedia — “Drop D tuning”en.wikipedia.org · accessed 25 Jul 2026
- Encyclopædia Britannica, “Equal temperament”britannica.com · accessed 11 Aug 2026
About this page: A440/ISO 16 history and string frequencies are drawn from Sources 1–2; open and modal tunings from Sources 3–4. Standard-derived tunings (half step down, Drop D, Double Drop D) are computed directly from the verified reference frequencies rather than a separate citation.
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