Standard Method of Tuning the Guitar

In the standard method of tuning, the reference notes are identical in tone, thus their frequencies are equal in pitch. The pegs of a string are adjusted until the tones of an open string and a note played at the 5th fret (4th fret on the 5th*/B string) of the next lower string are unison. From the lowest string, each next higher string is tuned to a perfect 4th (B is a major 3rd above G) interval increase in pitch from the string before it.

Comparing the tone of a properly tuned guitar string to the tone of a fretted note a 4th interval higher than the lower adjacent open string; either the open string or the string that plays the fretted note is adjusted until the tones match. In standard tuning of the guitar, each open string is tuned to a perfect 4th interval higher than the string before it, except for the B string which is a major 3rd interval higher in pitch than the open G string.