A standard six-string guitar is tuned to six specific pitches: E-A-D-G-B-E (lowest to highest). These frequencies are determined by equal temperament tuning, a system that divides the octave into twelve equal semitones using precise mathematical ratios.
Equal temperament was standardized in the 17th century and adopted universally for practical reasons: it allows instruments to play in any key without major pitch distortion. On a guitar, this means each fret represents exactly one semitone, and any fret on any string produces a predictable, consistent pitch.
Understanding the standard frequencies helps with tuning accuracy, transposition, and diagnosing tuning issues.
The Six Strings and Their Frequencies
Low E (E2): 82.41 Hz
A2: 110 Hz
D3: 146.83 Hz
G3: 196 Hz
B3: 246.94 Hz
High E (E4): 329.63 Hz
These are the open-string frequencies when the guitar is in standard tuning. Each string can produce higher pitches up the fretboard. The 12th fret on any string produces an octave higher than the open string (double the frequency).
These frequencies represent concert pitch (A4 = 440 Hz) standard tuning. If a guitar is tuned to an alternate standard (like A432 or A435), all frequencies shift proportionally lower.
Why These Frequencies?
The interval pattern between strings reflects a design choice balancing playability and harmonic coherence. From low E to A is a perfect fourth (5 semitones). A to D is a perfect fourth. D to G is a perfect fourth. G to B is a major third (4 semitones—notably different from the pattern). B to high E is a perfect fourth.
This pattern (four perfect fourths, one major third) creates voicings that guitarists recognize instantly. Open E major (E-G#-B) strings 6-4-2 sound good together. Open A major strings 5-3-1 align nicely. The major third between G and B breaks the fourth pattern but creates harmonic richness.
Alternative patterns exist—seven-string guitars, 12-string guitars, and tuned instruments use different strings and intervals—but six-string standard tuning has dominated for centuries because it’s practical and musical.
Tuning by Interval Relationships
Rather than memorizing or looking up exact Hz values, guitarists often tune by interval relationships. If you know one string’s pitch, you can tune the others relative to it.
Play E (string 6) and D (string 4). The interval should be one whole step down, or 2 semitones. It should sound like the opening of “The Star-Spangled Banner” (which jumps by this interval).
Play A (string 5) and high E (string 1). The interval is a perfect fourth (5 semitones)—open, resonant, stable.
Learning these interval relationships makes tuning by ear practical, even without knowing exact frequencies.
Factors That Affect Tuning Stability
Temperature: Cold contracts strings, lowering pitch. Heat expands strings, raising pitch. A guitar brought from outdoors into a warm room may shift sharp. Allow 15-20 minutes to stabilize.
Humidity: Extreme humidity swells wood, affecting string height and tension. Consistent humidity (40-60%) is ideal for tuning stability.
String age: New strings have high internal tension and stretch for 24-48 hours, causing pitch to drop. Stretch new strings manually before tuning to speed stabilization. Worn strings weaken and go flat faster than fresh strings.
Bridge and nut friction: The bridge transmits string vibration to the body. If there’s friction or slippage, tuning drifts. High-quality bridges and nuts maintain tension better.
Fretboard wear: Frets wear over years, changing playability and requiring occasional fret dressing. This doesn’t usually affect open-string tuning but can affect the playability of higher frets.
Alternate Tunings and Frequency Changes
Musicians use alternate tunings for specific sounds or styles. Drop D tuning lowers the low E string to D (73.42 Hz). Open G tunes to G-B-D-G-B-D. Each tuning shifts frequencies differently.
When transposing tuning, remember: each semitone up multiplies frequency by 2^(1/12) ≈ 1.0595. Each semitone down divides by the same ratio. Drop the low E by one semitone (E to Eb) and it becomes 77.78 Hz. Drop two semitones (E to D) and it becomes 73.42 Hz.
Alternate tunings are creative tools but require understanding how frequency relationships shift.
Frequently Asked Questions
What if my tuner doesn’t show Hz values, just note names?
Most modern tuners display note names (E, A, D, etc.) and whether you’re sharp or flat of target. If you want Hz values, use a spectrum analyzer app or a tuner that includes frequency display. For standard tuning, the note names alone are sufficient.
How often should I tune my guitar?
Before every session, at minimum. Professional players check tuning every 10-15 minutes during rehearsal or recording because environmental changes and string stretch cause pitch drift. If you’re just playing casually, once per session is acceptable, but beginning the session in-tune is crucial.
Can I use a piano to tune my guitar?
Yes. Play the corresponding note on a piano and match it on your guitar. A4 on the piano = high E on the guitar (one octave up from open E). This works well for reference pitches but is slower than using a tuner.
Why is the B string different (major third instead of perfect fourth)?
The major third between G and B is a historical design choice. It enables certain chord voicings and harmonic relationships that work well for guitar. If all strings were perfect fourths apart, chord shapes would be different and less intuitive for guitarists.
Vincent is a pitch detection and vocal analysis writer at OnlinePitchDetector. He focuses on pitch recognition, vocal frequency analysis, singing tools, and real-time audio testing for singers, musicians, producers, and beginners.