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Dodecatonic Fret Numbering

Revision as of 09:57, 3 November 2026 by TallKite (talk | contribs) (added "h10" for 19edo's 15th fret)

Dodecatonic fret numbering (DFN for short) is a method of naming frets in tablature. Each fret is numbered to match the nearest 12edo fret. If multiple frets map to the same 12edo fret, they are differentiated with letters a, b, c, etc. If a fret falls roughly midway between two 12edo frets (within about 6¢ of the midpoint), it's numbered as the smaller option, and lettered as "h", short for halfway. If there is only one fret in a category (other than possibly an "h" fret), it is unlettered. Thus 24edo runs 0 0h 1 1h 2 2h 3...

0h, 1h, etc. can optionally be written as 0.5, 1.5, etc. 0h can optionally be written as h.

Applications

DFN tablature is designed for the professional guitarist who mainly plays 12edo guitar, but is sometimes hired to play microtonal music on a guitar they don't own. They would generally prefer tablature over score. DFN tab would be much easier for them to read than tab with conventional fret numbering. Upon seeing e.g. "6a" or "7", their muscle memory will place them in the general vicinity of the proper fret. Markings on the side of the guitar neck can group the frets into categories, making the tablature even easier to read. Possibly fretwire of two different colors could be used, to make the grouping even more obvious.

19edo example
19edo 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
cents 0 63 126 189 253 316 379 442 505 568 632 695 758 821 884 947 1011 1074 1137 1200
fret name 0 1a 1b 2 2h 3 4a 4b 5 6a 6b 7 8a 8b 9 9h 10 11a 11b 12
markings |_____| |_____| * |_____| * |_____| * |_____| |*____| |______| *
fretwire gold silver gold silver gold silver gold silver gold silver gold silver

DFN makes 24edo tablature easier to read, and even a guitarist who owns a 24edo guitar may prefer DFN tab.

DFN applies to all frettings: edos, JI, etc. Fretlets can be named as if all fretlets extended across the entire fretboard. But that isn't necessary if the fretlets naturally group into full frets, as with True Temperament frets.

DFN has the advantage that adding or removing a single fret or fretlet won't affect the naming of most or all of the other frets.

edo 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
15 cents 0 80 160 240 320 400 480 560 640 720 800 880 960 1040 1120 1200
fret 0 1 2a 2b 3 4 5 6a 6b 7 8 9 10a 10b 11 12
16 cents 0 75 150 225 300 375 450 525 600 675 750 825 900 975 1050 1125 1200
fret 0 1 1h 2 3 4 4h 5 6 7 7h 8 9 10 10h 11 12
17 cents 0 71 141 212 282 353 424 494 565 635 706 776 847 918 988 1059 1129 1200
fret 0 1a 1b 2 3 3h 4 5 6a 6b 7 8 8h 9 10 11a 11b 12
19 cents 0 63 126 189 253 316 379 442 505 568 632 695 758 821 884 947 1011 1074 1137 1200
fret 0 1a 1b 2 2h 3 4a 4b 5 6a 6b 7 8a 8b 9 9h 10 11a 11b 12
22 cents 0 55 109 164 218 273 327 382 436 491 545 600 655 709 764 818 873 927 982 1036 1091 1145 1200
fret 0 0h 1 2a 2b 3a 3b 4a 4b 5 5h 6 6h 7 8a 8b 9a 9b 10a 10b 11 11h 12
24 cents 0 50 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 1000 1050 1100 1150 1200
fret 0 0h 1 1h 2 2h 3 3h 4 4h 5 5h 6 h6 7 7h 8 8h 9 9h 10 10h 11 11h 12
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

The open string is always named "0", and the octave fret is always named "12".

Starting with 29edo, the first fret is too small to be named 0h. Naming it 0a or 0b would cause inconsistencies with frets in the "12" category, which runs 28\29=12a, 29\29=12, and 30\29=12c. For example, fret 0b plus an octave would be not 12b but 12c. To avoid this, the rule is "the zeros must match the twelves". Therefore the first fret in larger edos is named 0c.

26edo 27edo 29edo 31edo 34edo 38edo 41edo Kite guitar
cents fret cents fret cents fret cents fret cents fret cents fret cents fret cents fret
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
1 46 0h 44 0h 41 0c 39 0c 35 0c 32 0c 29 0c 59 1a 1
2 92 1a 89 1a 83 1a 77 1a 71 1a 63 1a 59 1a 117 1b 2
3 138 1b 133 1b 124 1b 116 1b 106 1b 95 1b 88 1b 176 2a 3
4 185 2a 178 2a 166 2a 155 1h 141 1c 126 1c 117 1c 234 2b 4
5 231 2b 222 2b 207 2b 194 2a 176 2a 158 2a 146 1h 293 3a 5
6 277 3a 267 3a 248 2h 232 2b 212 2b 189 2b 176 2a 351 3h 6
7 323 3b 311 3b 290 3a 271 3a 247 2h 221 2c 205 2b 410 4 7
8 369 4a 356 3h 331 3b 310 3b 282 3a 253 2h 234 2c 468 5a 8
9 415 4b 400 4 372 4a 348 3h 318 3b 284 3a 263 3a 527 5b 9
10 462 5a 444 4h 414 4b 387 4a 353 3h 316 3b 293 3b 585 6a 10
11 508 5b 489 5a 455 4h 426 4b 388 4a 347 3h 322 3c 644 6h 11
12 554 5h 533 5b 497 5a 465 5a 424 4b 379 4a 351 3h 702 7 12
13 600 6 578 6a 538 5b 503 5b 459 5a 411 4b 380 4a 761 8a 13
14 646 6h 622 6b 579 6a 542 5c 494 5b 442 4c 410 4b 820 8b 14
15 692 7a 667 7a 621 6b 581 6a 529 5c 474 5a 439 4c 878 9a 15
16 738 7b 711 7b 662 7a 619 6b 565 6a 505 5b 468 5a 937 9b 16
17 785 8a 756 7h 703 7b 658 7a 600 6b 537 5c 498 5b 995 10 17
18 831 8b 800 8 745 7h 697 7b 635 6c 568 6a 527 5c 1054 10h 18
19 877 9a 844 8h 786 8a 735 7c 671 7a 600 6b 556 5h 1112 11 19
20 923 9b 889 9a 828 8b 774 8a 706 7b 632 6c 585 6a 1171 12a 20
21 969 10a 933 9b 869 9a 813 8b 741 7c 663 7a 615 6b 1229 12b 21
22 1015 10b 978 10a 910 9b 852 8h 776 8a 695 7b 644 6h 1288 13 22
23 1062 11a 1022 10b 952 9h 890 9a 812 8b 726 7c 673 7a 1346 13h 23
24 1108 11b 1067 11a 993 10a 929 9b 847 8h 758 8a 702 7b 1405 14 24
25 1154 11h 1111 11b 1034 10b 968 10a 882 9a 789 8b 732 7c 1463 15a 25
26 1200 12 1156 11h 1076 11a 1006 10b 918 9b 821 8c 761 8a 1522 15b 26
27 1246 12h 1200 12 1117 11b 1045 10h 953 9h 853 8h 790 8b 1580 16a 27
28 1244 12h 1159 12a 1084 11a 988 10a 884 9a 820 8c 1639 16b 28
29 1200 12 1123 11b 1024 10b 916 9b 849 8h 1698 17 29
30 1241 12c 1161 12a 1059 11a 947 9h 878 9a 1756 18a 30
31 1200 12 1094 11b 979 10a 907 9b 1815 18b 31
32 1239 12c 1129 11c 1011 10b 937 9c 1873 19a 32
33 1165 12a 1042 10c 966 10a 1932 19b 33
34 1200 12 1074 11a 995 10b 1990 20 34
35 1235 12c 1105 11b 1024 10c 2049 20h 35
36 1137 11c 1054 10h 2107 21 36
37 1168 12a 1083 11a 2166 22a 37
38 1200 12 1112 11b 2224 22b 38
39 1232 12c 1141 11c 2283 23a 39
40 1171 12a 2341 23b 40
41 1200 12 2400 24 41
26edo 27edo 29edo 31edo 34edo 38edo 41edo Kite guitar


Various EDOs smaller than 15

edo 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 notes
9 cents 0 133 267 400 533 667 800 933 1067 1200 omits
2, 6 & 10
fret 0 1 3 4 5 7 8 9 11 12
10 cents 0 120 240 360 480 600 720 840 960 1080 1200 omits
3 and 9
fret 0 1 2 4 5 6 7 8 10 11 12
11 cents 0 109 218 327 436 545 655 764 873 982 1091 1200 omits
6
fret 0 1 2 3 4 5 7 8 9 10 11 12
13 cents 0 92 185 277 369 462 554 646 738 831 923 1015 1108 1200 doubles
6
fret 0 1 2 3 4 5 6a 6b 7 8 9 10 11 12
14 cents 0 86 171 257 343 429 514 600 686 771 857 943 1029 1114 1200 doubles
3 and 9
fret 0 1 2 3a 3b 4 5 6 7 8 9a 9b 10 11 12

Notes

See also KDF fret numbering for the Kite guitar.

Using "h" to name frets causes the grouping markings on the side of the neck to be asymmetrical, in the sense that the upper octave is not a mirror image of the lower octave. One solution is to rename e.g. 19edo's 9h as h10. Mnemonic: 9h means "nine plus a half", and h10 means "halfway to ten". That leads to these pleasingly symmetrical markings:

19edo example
19edo 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
cents 0 63 126 189 253 316 379 442 505 568 632 695 758 821 884 947 1011 1074 1137 1200
fret name 0 1a 1b 2 2h 3 4a 4b 5 6a 6b 7 8a 8b 9 h10 10 11a 11b 12
markings |_____| |_____| * |_____| * |_____| * |_____| * |_____| |______| *
fretwire gold silver gold silver gold silver gold silver gold silver gold silver

If taking this approach, care must be taken to never use 9h or 9.5 in tab for a 19edo guitar marked this way.

DFN was devised by Kite Giedraitis in late 2026.

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