64/27

64/27 is the Pythagorean minor tenth. It functions as an octave above a pythagorean minor third in just intonation.

Interval information

Ratio	64/27
Factorization	26 × 3-3
Monzo	[6 -3⟩
Size in cents	1494.135¢
Name	Pythagorean minor tenth
Color name	w10, wa 10th
FJS name	[math]\displaystyle{ \text{m10} }[/math]
Tenney norm (log2 nd)	10.7549
Weil norm (log2 max(n, d))	12
Wilson norm (sopfr(nd))	21
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Trivia

This interval is a common ultrawide aspect ratio, often marketed as 21:9, which simplifies to 7:3. 64/27 differs from 21/9 by 64/63, the septimal comma.

See also

• 32/27 – its octave reduction
• 81/64 – its tritave complement
• Gallery of just intervals
• Pythagorean tuning