Choose a note, octave, and reference pitch to calculate frequency in hertz. The standard-tuning table gives quick frequency and MIDI references for all six guitar strings.
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Key takeaways
- At A4 = 440 Hz, standard guitar open strings run from E2 at about 82.41 Hz to E4 at about 329.63 Hz.
- Every octave doubles frequency; moving down one octave halves it.
- Changing the A4 reference moves every equal-tempered note proportionally.
- Tension changes with frequency squared, so small pitch changes have a larger tension effect.
How to use this: Use these frequencies as a tuning reference, then confirm the result against your own tuner and the reference pitch you actually play to.
Quick answer
Use note, octave, and reference pitch together
A guitar string frequency is not defined by the note letter alone. E2 is about 82.41 Hz while E4 is about 329.63 Hz at A4 = 440 Hz, so the octave number must be correct before the result can guide tuning or tension work.
Pitch class alone cannot identify one frequency.
Change it only when the session or ensemble requires it.
A pitch change has a larger tension effect than its percentage suggests.
How to use the guitar string frequency calculator
Choose the open-string note, set the correct scientific octave, and confirm the A4 reference used by the tuner. Use the returned hertz value as a target or as an input to a physical string comparison.
- Select the note name and octave for the open string.
- Leave A4 at 440 Hz unless a recording, orchestra, or historical setup specifies another reference.
- Compare the result with the standard-tuning table to catch octave errors.
- When estimating tension, keep scale and string unchanged so the frequency effect is isolated.
Worked example: the same open string at three tuning references
A4 = 440 Hz is the common default, not a law. Some orchestras tune to A4 = 442 Hz for a slightly brighter ensemble sound, and early-music groups can tune closer to A4 = 415 Hz, roughly a semitone flat of modern pitch. The note name stays "E2" in every case; only the cycles-per-second behind it change.
| A4 reference | Open low E (E2) | Same-string tension vs. 440 Hz |
|---|---|---|
| A4 = 415 Hz | 77.73 Hz | About 89% of the 440 Hz baseline |
| A4 = 440 Hz | 82.41 Hz | 100% baseline |
| A4 = 442 Hz | 82.78 Hz | About 101% of the 440 Hz baseline |
Switch the reference in the calculator above to see every open string move together, not just the low E.
Checks for a surprising frequency result
A result that is exactly double or half the expected value usually points to an octave mismatch. A small uniform shift across every note usually comes from a different A4 reference.
- Confirm that string 6 in standard tuning is E2, not E3.
- Remember that enharmonic names such as A-sharp and B-flat share a frequency in equal temperament.
- Use a tuner to measure the instrument; this calculator supplies the target rather than listening.
- Separate fundamental frequency from upper harmonics shown by spectrum tools.
Note frequency versus a physical-string calculation
This page answers “what frequency should this musical note have?” from note, octave, and A4 reference. A physical-string calculator answers a different question by combining speaking length, tension, and mass per unit length.
Use the note result as the target frequency, then use the tension calculator when gauge and scale length enter the decision. Keeping those two jobs separate makes an unexpected answer easier to diagnose.
- Use the note calculator for tuning targets, transposition, and A4-reference changes.
- Use the tension calculator for gauge, scale, material, and setup comparisons.
- Use a tuner or spectrum tool to measure a played string rather than predict it.
- Expect harmonics above the fundamental when viewing a recorded spectrum.
The note-to-frequency equation
With A4 as the reference, equal temperament uses f = A4 × 2⁽ᵐ⁻⁶⁹⁾⁄¹², where m is the MIDI note number. Every octave doubles frequency and every descending octave halves it.
Frequency matters directly to tension because tension changes with the square of frequency. Dropping a string by a whole step reduces its tension substantially unless gauge or scale length changes.
Standard tuning frequencies
At A4 = 440 Hz, the open strings in standard tuning range from E2 at about 82.41 Hz to E4 at about 329.63 Hz.
| String | Note | Frequency | Octave relation |
|---|---|---|---|
| 1 | E4 | 329.63 Hz | Two octaves above E2 |
| 2 | B3 | 246.94 Hz | Perfect fifth above E3 |
| 3 | G3 | 196.00 Hz | One octave above G2 |
| 4 | D3 | 146.83 Hz | One octave above D2 |
| 5 | A2 | 110.00 Hz | Two octaves below A4 |
| 6 | E2 | 82.41 Hz | Lowest standard guitar string |
Changing the A4 reference
Most modern tuning references use A4 = 440 Hz, but it is not universal: some orchestras tune to A4 = 442 Hz for a brighter ensemble sound, and early-music groups can tune closer to A4 = 415 Hz, roughly a semitone flat. Changing the reference moves every note proportionally; it does not alter the interval structure.
Reference material
Technical references
Use these manufacturer references when you need product-specific tension or setup information. They were last reviewed on ; the gauge suggestions on this page remain starting points because strings and instruments vary.
Before you change strings
Save your current setup, change one variable at a time, and recheck tuning, neck relief, action, and intonation after the new strings settle. If a result looks inconsistent with your instrument or a manufacturer's data, send the setup details through the contact page.