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A '''perfect consonance''' is one of the most consonant intervals; they are usually extremely easy to sing and recognize by ear. The set of perfect consonances is equivalent in most systems of theory to the '''3-odd-limit''', which is the set of intervals wherein the highest allowable odd in the numerator and denominator is 3. It is the smallest odd-limit containing intervals of the 3-limit.

== Table of 3-odd-limit intervals ==
Reduced to an octave, the intervals of the 3-odd-limit are:
{| class="wikitable"
!Interval
!Cents
!Name
|-
|1/1
|0.0
|Unison
|-
|4/3
|498.0
|Perfect 4th
|-
|3/2
|702.0
|Perfect 5th
|-
|2/1
|1200.0
|Octave
|}

== Approximation by edos ==
All edos are consistent to the 3-odd-limit, because the requirement is simply to map 3/1 somewhere between 1800c and 2400c, which is a property of all edos. The first edo that is distinctly consistent to the 3-odd-limit is 3edo. However, the first edos that tune all its intervals reasonably accurately are 5edo and 7edo, outlining the basic structures of equipentatonic and equiheptatonic scales.

== Intervals of the 3-odd-limit ==
More info at [[5-odd-limit#Perfect consonances]].