45edo divides the octave into 45 equal parts of 26.667 cents. It is the optimal patent val for flattone temperament, the 7-limit 525/512 planar avicennmic temperament, the 11-limit calliope temperament tempering out 45/44 and 81/80, and the rank four temperament tempering out 45/44. It tempers out 81/80, 3125/3087, 525/512, 875/864 and 45/44. It is a flat-tending system in the 7-limit, with 3, 5 and 7 all flat, but the 11 is sharp. Also supports messed-up ennealimmal, if you want. Since 45 is a multiple of 5 and 9, it can be used to model Indonesian music in both Slendro (~ 5edo) and Pelog (~ modes of 9edo) tunings.

Step # ET Just Difference
(ET minus Just)
Ups and Downs Notation
Cents Interval Cents
0 unison 1 D
1 26.666
2 53.333
3 80.0
4 106.666
5 133.333
6 160
7 186.666
8 213.333
9 240
10 266.666
11 293.333
12 320
13 346.666
14 373.333
15 400
16 426.666
17 453.333
18 480
19 506.666
20 533.333
21 560
22 586.666
23 613.333
24 640
25 666.666
26 693.333
27 720
28 746.666
29 773.333
30 800
31 826.666
32 853.333
33 880
34 906.666
35 933.333
36 960
37 986.666
38 1013.333
39 1040
40 1066.666
41 1093.333
42 1120
43 1146.666
44 1173.333
45 1200 Octave D