12edo

12edo is the equal tuning featuring steps of (1200/12) = 100 cents, by definition, as 12 steps stack to the octave 2/1. It is the dominant tuning system in the world, and as such is covered by Xenbase for completeness as it is not 'xenharmonic'.

Theory

JI approximation

12edo is conventionally seen as a 2.3.5 edo, though perhaps more salient to conventional Western musical practice is the fact that it contains the basic diatonic scale, 2-2-1-2-2-2-1.

Approximation of prime harmonics in example edo

Harmonic		2	3	5	7	11	13	17	19	23
Error	Absolute (¢)	+0.0	-2.0	+13.7	+31.2	+48.7	-40.5	-5.0	+2.5	-28.3
	Relative (%)	+0.0	-2.0	+13.7	+31.2	+48.7	-40.5	-5.0	+2.5	-28.3
Steps (reduced)