The intervals of 5-limit just intonation (prime limit, not odd limit) are ratios involving only the powers of 2, 3, and 5. The fundamental intervals are the superparticular ratios 2/1 (the octave), 3/2 (the perfect fifth) and 5/4 (the major third). That is, the notes of the major triad are in the ratio 1:5/4:3/2 or 4:5:6.
In all tunings, the major third is equivalent to two major seconds. However, because just intonation does not allow the irrational ratio of /2, two different frequency ratios are used: the major tone (9/8) and the minor tone (10/9).
The intervals within the diatonic scale are shown in the table below.
| Names | Ratio | 12ET interval (in cents) | Definition | 53ET interval (in Holdrian commas) | 53ET interval (in cents) | Arel-Ezgi-Uzdilek notation (a 53ET-based notation) | Complement | ||
|---|---|---|---|---|---|---|---|---|---|
| 1/1 | 0.00 | 0 | 0 | 0 | octave | ||||
| 81/80 | 21.51 | 0 | c or T - t | 1 | 22.64 | semi-diminished octave | |||
| diesis diminished second | 128/125 | 41.06 | 0 | D or S - x | 2 | 45.28 | augmented seventh | ||
| lesser chromatic semitone minor semitone augmented unison | 25/24 | 70.67 | 100 | x or t - S or T - L | 3 | 67.92 | diminished octave | ||
| Pythagorean minor second Pythagorean limma | 256/243 | 90.22 | 100 | Λ | 4 | 90.57 | Pythagorean major seventh | ||
| greater chromatic semitone wide augmented unison | 135/128 | 92.18 | 100 | X or T - S | 4 | 90.57 | narrow diminished octave | ||
| major semitone limma minor second | 16/15 | 111.73 | 100 | S | 5 | 113.21 | major seventh | ||
| large limma acute minor second | 27/25 | 133.24 | 100 | L or S + c or T - x | 6 | 135.85 | grave major seventh | ||
| grave tone grave major second | 800/729 | 160.90 | 200 | τ or Λ + x or t - c | 7 | 158.49 | acute minor seventh | ||
| minor tone lesser major second | 10/9 | 182.40 | 200 | t | 8 | 181.13 | minor seventh | ||
| major tone Pythagorean major second greater major second | 9/8 | 203.91 | 200 | T or t + c | 9 | 203.77 | Pythagorean minor seventh | ||
| diminished third | 256/225 | 223.46 | 200 | S + S | 10 | 226.42 | augmented sixth | ||
| semi-augmented second | 125/108 | 253.08 | 300 | t + x | 11 | 249.06 | semi-augmented sixth | ||
| augmented second | 75/64 | 274.58 | 300 | T + x | 12 | 271.70 | diminished seventh | ||
| Pythagorean minor third | 32/27 | 294.13 | 300 | T + Λ | 13 | 294.34 | Pythagorean major sixth | ||
| minor third | 6/5 | 315.64 | 300 | T + S | 14 | 316.98 | major sixth | ||
| acute minor third | 243/200 | 333.18 | 300 | T + L | 15 | 339.62 | grave major sixth | ||
| grave major third | 100/81 | 364.81 | 400 | T + τ | 16 | 362.26 | acute minor sixth | ||
| major third | 5/4 | 386.31 | 400 | T + t | 17 | 384.91 | minor sixth | ||
| Pythagorean major third | 81/64 | 407.82 | 400 | T + T | 18 | 407.55 | Pythagorean minor sixth | ||
| classic diminished fourth | 32/25 | 427.37 | 400 | T + S + S | 19 | 430.19 | classic augmented fifth | ||
| classic augmented third | 125/96 | 456.99 | 500 | T + t + x | 20 | 452.83 | classic diminished sixth | ||
| wide augmented third | 675/512 | 478.49 | 500 | T + t + X | 21 | 475.47 | narrow diminished sixth | ||
| perfect fourth | 4/3 | 498.04 | 500 | T + t + S | 22 | 498.11 | perfect fifth | ||
| acute fourth[1] | 27/20 | 519.55 | 500 | T + t + L | 23 | 520.75 | grave fifth | ||
| classic augmented fourth | 25/18 | 568.72 | 600 | T + t + t | 25 | 566.04 | classic diminished fifth | ||
| augmented fourth | 45/32 | 590.22 | 600 | T + t + T | 26 | 588.68 | diminished fifth | ||
| diminished fifth | 64/45 | 609.78 | 600 | T + t + S + S | 27 | 611.32 | augmented fourth | ||
| classic diminished fifth | 36/25 | 631.29 | 600 | T + t + S + L | 28 | 633.96 | classic augmented fourth | ||
| grave fifth | 40/27 | 680.45 | 700 | T + t + S + t | 30 | 679.25 | acute fourth | ||
| perfect fifth | 3/2 | 701.96 | 700 | T + t + S + T | 31 | 701.89 | perfect fourth | ||
| narrow diminished sixth | 1024/675 | 721.51 | 700 | T + t + S + S + S | 32 | 724.53 | wide augmented third | ||
| classic diminished sixth | 192/125 | 743.01 | 700 | T + t + S + L + S | 33 | 747.17 | classic augmented third | ||
| classic augmented fifth | 25/16 | 772.63 | 800 | T + t + S + T + x | 34 | 769.81 | classic diminished fourth | ||
| Pythagorean minor sixth | 128/81 | 792.18 | 800 | T + t + S + T + Λ | 35 | 792.45 | Pythagorean major third | ||
| minor sixth | 8/5 | 813.69 | 800 | (T + t + S + T) + S | 36 | 815.09 | major third | ||
| acute minor sixth | 81/50 | 835.19 | 800 | (T + t + S + T) + L | 37 | 837.74 | grave major third | ||
| grave major sixth | 400/243 | 862.85 | 900 | (T + t + S + T) + τ | 38 | 862.85 | acute minor third | ||
| major sixth | 5/3 | 884.36 | 900 | (T + t + S + T) + t | 39 | 883.02 | minor third | ||
| Pythagorean major sixth | 27/16 | 905.87 | 900 | (T + t + S + T) + T | 40 | 905.66 | Pythagorean minor third | ||
| diminished seventh | 128/75 | 925.42 | 900 | (T + t + S + T) + S + S | 41 | 928.30 | augmented second | ||
| semi-augmented sixth | 216/125 | 946.92 | 800 | (T + t + S + T) + S + L | 42 | 946.92 | semi-augmented second | ||
| augmented sixth | 225/128 | 976.54 | 1000 | (T + t + S + T) + T + x | 43 | 973.58 | diminished third | ||
| 16/9 | 996.09 | 1000 | (T + t + S + T) + T + Λ | 44 | 996.23 | greater major second Pythagorean major second | |||
| greater minor seventh | 9/5 | 1017.60 | 1000 | (T + t + S + T) + T + S | 45 | 1018.87 | lesser major second | ||
| acute minor seventh | 729/400 | 1039.10 | 1000 | (T + t + S + T) + T + L | 46 | 1041.51 | grave major second | ||
| grave major seventh | 50/27 | 1066.76 | 1100 | (T + t + S + T) + T + τ | 47 | 1064.15 | acute minor second | ||
| major seventh | 15/8 | 1088.27 | 1100 | (T + t + S + T) + T + t | 48 | 1086.79 | minor second | ||
| narrow diminished octave | 256/135 | 1107.82 | 1100 | (T + t + S + T) + t + S + S | 49 | 1109.43 | wide augmented unison | ||
| Pythagorean major seventh | 243/128 | 1109.78 | 1100 | (T + t + S + T) + T + T | 49 | 1109.43 | Pythagorean minor second | ||
| diminished octave | 48/25 | 1129.33 | 1100 | (T + t + S + T) + T + S + S | 50 | 1132.08 | augmented unison | ||
| augmented seventh | 125/64 | 1158.94 | 1200 | (T + t + S + T) + T + t + x | 51 | 1154.72 | diminished second | ||
| semi-diminished octave | 160/81 | 1178.49 | 1200 | (T + t + S + T) + T + t + x + c | 52 | 1177.36 | syntonic comma | ||
| octave | 2/1 | 1200.00 | 1200 | (T + t + S + T) + (T + t + S) | 53 | 1200.00 | unison |
(The Pythagorean minor second is found by adding 5 perfect fourths.)
The table below shows how these steps map to the first 31 scientific harmonics, transposed into a single octave.
| Harmonic | Musical Name | Ratio | Cents | 12ET Cents | 53ET Commas | 53ET Cents |
|---|---|---|---|---|---|---|
| 1 | unison | 1/1 | 0.00 | 0 | 0 | 0.00 |
| 2 | octave | 2/1 | 1200.00 | 1200 | 53 | 1200.00 |
| 3 | perfect fifth | 3/2 | 701.96 | 700 | 31 | 701.89 |
| 5 | major third | 5/4 | 386.31 | 400 | 17 | 384.91 |
| 7 | augmented sixth§ | 7/4 | 968.83 | 1000 | 43 | 973.58 |
| 9 | major tone | 9/8 | 203.91 | 200 | 9 | 203.77 |
| 11 | major fourth | 11/8 | 551.32 | 500 or 600 | 24 | 543.40 |
| 13 | acute minor sixth§ | 13/8 | 840.53 | 800 | 37 | 837.74 |
| 15 | major seventh | 15/8 | 1088.27 | 1100 | 48 | 1086.79 |
| 17 | limma§ | 17/16 | 104.96 | 100 | 5 | 113.21 |
| 19 | Pythagorean minor third§ | 19/16 | 297.51 | 300 | 13 | 294.34 |
| 21 | wide augmented third§ | 21/16 | 470.78 | 500 | 21 | 475.47 |
| 23 | classic diminished fifth§ | 23/16 | 628.27 | 600 | 28 | 633.96 |
| 25 | classic augmented fifth | 25/16 | 772.63 | 800 | 34 | 769.81 |
| 27 | Pythagorean major sixth | 27/16 | 905.87 | 900 | 40 | 905.66 |
| 29 | minor seventh§ | 29/16 | 1029.58 | 1000 | 45 | 1018.87 |
| 31 | augmented seventh§ | 31/16 | 1145.04 | 1100 | 51 | 1154.72 |