Guitar Tuning Frequency Chart: Notes, Octaves and A4 Reference

Standard tuning frequency chart

Six strings, six targets, one reference pitch. Read the row for the string you are tuning, and read the octave number with the note name — E2 and E4 are the same letter at very different frequencies.

These values assume 12-tone equal temperament, where every semitone is a factor of 2^(1/12) and A4 is the one pitch the reference fixes. Two decimals is a reading convention, not a precision claim: 82.41 Hz and 82.4069 Hz name the same target.

Reading the octave number

The number after the note name is the octave, in scientific pitch notation. A4 is the A that the reference pitch fixes, and C4 is middle C on a piano. Each octave is exactly double the one below it, which is why the chart's fourth column is simply twice its third column.

That doubling gives you a fast check. The open 6th string is E2 at 82.41 Hz. Its octave, E3, is 164.81 Hz, and the open 1st string is E4 at 329.63 Hz — double E3, and four times the 6th string.

On a guitar, the 12th fret is the octave. Play the 12th-fret harmonic of any open string and it should sound the same note name one octave above the open string. If a tuner shows the right letter but an octave number you did not expect, you are one doubling away from the target, not one semitone away.

Changing the A4 reference

Equal temperament fixes the ratios between notes, not their absolute frequencies. Only A4 is set by convention, and ISO 16:1975 specifies 440 Hz for it. Change the reference and every note on the instrument moves by the same proportion, so one multiplication covers all six strings. ISO 16:1975, Acoustics — Standard tuning frequency (Standard musical pitch)

Worked example: at A4 = 432 Hz the multiplier is 432 ÷ 440, or about 0.9818. The 5th string target becomes 110.00 × 0.9818 = 108.00 Hz. Nothing about the guitar changes; the target does.

Tuners commonly offer a calibration or reference setting that covers a range like this. Two values you may meet: 415 Hz, the reference used for Baroque pitch, and 432 Hz, which some players prefer. Neither is a fault. If you change that setting on your device, the arithmetic above is what it is doing on your behalf — and the table lets you check the result.

What your tuner reading means

A frequency chart gives you the target. This table covers the cases where the reading and the target disagree.

How to use this chart

1. Confirm which tuning you are in. This chart is standard tuning. If you are in Drop D, half step down, open C, or another tuning, the open-string targets are different — the next section lists a few of them.
2. Read the target for the string you are tuning, not just the note name. The octave number is what separates E2 from E4.
3. Check your tuner's reference setting. It should read 440 Hz unless you have deliberately chosen another value. ISO 16:1975 specifies 440 Hz for A4.
4. Bring the string to its target and stop when the indicator centers. Most players tune up to the note rather than down to it; either way, the number in the chart is the destination.
5. Verify the octave. Play the 12th-fret harmonic and listen for the same note name one octave above the open string.
6. Re-check a few minutes later. A string that has just moved continues to settle, so retune and confirm the numbers still land where the chart says they should.

Other tunings and instruments

The same arithmetic produces every other tuning. These are computed from the same 440 Hz definition, 6th string to 1st string unless noted.

Half step down sits exactly one semitone below standard — a factor of 2^(1/12), about 0.9439 — so its numbers are not rounded versions of the standard ones. The half step down tuning walkthrough on this site covers which strings move and what to play in that tuning; this chart only covers the frequencies.

Open C is a different case, because the open strings already sound a C major chord. Once the tuning is set from the numbers above, the open C chord shapes reference covers what to play without moving your hand shape.

What this chart cannot tell you

• It does not listen to your instrument. There is no microphone on this page. Every number here comes from a formula, not from a measurement of your guitar.
• Equal temperament only. The values assume 12-tone equal temperament at the stated reference. Instruments or ensembles working in another temperament will not match them exactly.
• Rounded values. Two decimals is a reading convention. At E2 one cent is roughly 0.05 Hz, and at E4 it is roughly 0.19 Hz, so treat these numbers as targets for tuning by ear and eye, not as bench calibration figures.
• Open strings only. The chart gives open-string targets. Fretted notes have their own frequencies, and how closely a fretted note matches its target depends on the instrument's setup.
• Not a setup guide. If the open strings are correct and the instrument still will not hold pitch or play in tune, that is a setup or maintenance question. For anything specific to your instrument — nut, saddle, relief, or whether it should carry a particular tuning at all — follow the manufacturer's official manual or have a qualified guitar tech look at it.

Frequently asked questions