Overview of harmonic intervals.
redundant ratio
new ratio
Just intonation
Septimal tuning
Bohlen-Pierce scale
Neutral/undecimal/tridecimal/Pythagorean/other
harmonic ratio
P = perfect, M = major, m = minor, A = augmented, d = diminished, n = neutral

Chromatic semitones:
0
P1
1
m2
2
M2
3
m3
4
M3
5
P4
6
tri
7
P5
8
m6
9
M6
10
m7
11
M7
12
P8
13
14
15
16
17
18
19
20
21
22
23
24
2P8
36
3P8
48
4P8
60
5P8
72
6P8

Frequency interval ratios:
1:1
P1
P1
BP0
Fundamental tone, 1st harmonic, 0 cents
2:2
2:1
P8
P8
1 octave, 2nd harmonic, 1st overtone, 1200 cents
3:3
3:2
P5
P5
Perfect fifth, 702 cents
3:1
P12(P5)
BP13 (1 tritave)
3rd harmonic, 2nd overtone
4:4
4:3
P4
P4
Perfect fourth, 498 cents
4:2 = 2:1
4:1
P15(2P8)
2 octaves, 4th harmonic, 3rd overtone
5:5
5:4
M3
386 cents
5:3
M6
BP6
884 cents
5:2
M10(M3)
5:1
M17(M3)
BP19(6)
5th harm, 4th over
6:6
6:5
m3
6:4 = 3:2
6:3 = 2:1
6:2 = 3:1
6:1
P19(P5)
6th harm, 5th over
7:7
7:6
m3
7:5
tritone (lesser)
BP4
7:4
m7
7:3
m10(m3)
BP10
7:2
m14(m7)
7:1
m21(m7)
BP23(10)
7th harm, 6th over
8:8
8:7
M2
8:6 = 4:3
8:5
m6
8:4 = 2:1
8:3
P11(P4)
8:2 = 4:1
8:1
P22(3P8)
3 octaves, h8
9:9
9:8
M2
204 cents
9:7
M3
BP3
9:6 = 3:2
9:5
m7
BP7
9:4
M9(M2)
9:3 = 3:1
9:2
M16(M2)
9:1
M23(M2)
BP26 (2 tritaves)
h9
10:10
10:9
M2 (lesser)
10:8 = 5:4
10:7
tritone (greater)
10:6 = 5:3
10:5 = 2:1
10:4 = 5:2
10:3
M13(M6)
10:2 = 5:1
10:1
M24(M3)
h10
11:11
11:10
n2
11:9
n3
11:8
und. semi-A4
11:7
und. A5
11:6
n7
11:5
n9
11:4
11:3
11:2
11:1
h11
12:12
12:10
n2
12:10 = 6:5
12:9 = 4:3
12:8 = 3:2
12:7
M6
12:6 = 2:1
12:5
m10(m3)
12:4 = 3:1
12:3 = 4:1
12:2 = 6:1
12:1
P26(P5)
h12
13:13
13:12
trid. 2/3
13:11
trid. m3
13:10
trid. semi-d4
13:9
trid. d5
13:8
trid. n6
13:7
13:6
13:5
13:4
13:3
13:2
13:1
h13
14:14
14:13
14:12 = 7:6
14:11
und. M3/d4
14:10 = 7:5
14:9
m6
14:8 = 7:4
14:7 = 2:1
14:6 = 7:3
14:5
tritone (lesser)
14:4 = 7:2
14:3
m17(m3)
14:2 = 7:1
14:1
m28(m7)
h14
15:15
15:14
m2
15:13
trid. 5/4
15:12 = 5:4
15:11
und. A4
15:10 = 3:2
15:9 = 5:3
15:8
M7
15:7
m9(m2)
BP9
15:6 = 5:2
15:5 = 3:1
15:4
M14(M7)
15:3 = 5:1
15:2
M21(M7)
15:1
M28(M7)
BP32(6)
h15
16:16
16:15
m2
16:14 = 8:7
16:13
n3
16:12 = 4:3
16:11
und. semi-d5
16:10 = 8:5
16:9
Pyth. m7
16:8 = 2:1
16:7
M9(M2)
16:6 = 8:3
16:5
m13(m6)
16:4 = 4:1
16:3
P18(P4)
16:2 = 8:1
16:1
P29(4P8)
4 octaves, h16


18:11
n6
18:7
M10(M3)
18:5
m14(m7)
18:1
M30(M2)
25:21
BP2
25:9
BP12
25:7
BP15(2)
25:3
BP25(12)
25:1
BP38(12)
27:25
BP1
27:14
M7
27:7
M14(M7)
BP16(3)
27:1
BP39 (3 tritaves)
32:15
m9(m2)
32:7
M16(M2)
32:5
m20(m6)
32:3
P25(P4)
32:1
P36(5P8)