Major fourth and minor fifth

Major fourth
InverseMinor fifth
Name
Other namesEleventh harmonic
Paramajor fourth
AbbreviationM4
Size
Semitones~5½
Interval class~5½
Just interval11:8
Cents
24-Tone equal temperament550
Just intonation551.32
Minor fifth
InverseMajor fourth
Name
Other namesEleventh subharmonic
Paraminor fifth
Abbreviationm5
Size
Semitones~6½
Interval class~5½
Just interval16:11
Cents
24-Tone equal temperament650
Just intonation648.68
The eleventh harmonic Playⓘ – shown using the Ben Johnston notation – can be approximated by the major fourth.
Just augmented fourth on C Playⓘ and its inverse, the just tritone on C Playⓘ

In music, the major fourth and minor fifth, also known as the paramajor fourth and paraminor fifth, are intervals from the quarter-tone scale, named by Ivan Wyschnegradsky to describe the tones surrounding the tritone (F♯/G♭) found in the more familiar twelve-tone scale,[1] as shown in the table below:

perfect fourth (para)major fourth tritone (para)minor fifth perfect fifth
In C: F ≊ Fhalf sharp F♯/G♭ ≊ Ghalf flat G
In cents: 500 550 600 650 700
  1. ^ Skinner, Miles Leigh (2007). Toward a Quarter-tone Syntax: Analyses of Selected Works by Blackwood, Haba, Ives, and Wyschnegradsky, p.25. ProQuest. ISBN 9780542998478.