Dodecatonic Fret Numbering

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 (temporary or permanent) 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

	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.

Various popular EDOs 15-24

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

Various popular larger EDOs

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

Using "h" to name frets causes the grouping markings on the side of the neck to be asymmetrical, in the sense that the upper half-octave is not a mirror image of the lower half-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". Another solution is to not use "h" at all. If taking either approach, avoid using 9h or 9.5 in tab for a 19edo guitar marked this way.

15edo

	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15
cents	0	80	160	240	320	400	480	560	640	720	800	880	960	1040	1120	1200
fret name	0	1	2a	2b	3	4	5	6a	6b	7	8	9	10a	10b	11	12
markings			|____*|				*	|_____|		*			|*_____|			* *

16edo with and without "h", two ways

	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16
cents	0	75	150	225	300	375	450	525	600	675	750	825	900	975	1050	1125	1200
fret name	0	1	h2	2	3	4	4h	5	6	7	h8	8	9	10	10h	11	12
			2a	2b		4a	4b				8a	8b		10a	10b
markings			|_____|		*	|_____|		*		*	|_____|		*	|_____|			* *
fret name	0	1	1h	2	3	4	4h	5	6	7	h8	8	9	10	h11	11	12
		1a	1b			4a	4b				8a	8b			11a	11b
markings		|_____|			*	|_____|		*		*	|_____|		*		|_____|		* *

450 is 4h/4b not h5/5a so that 5 and 7 need not have letters.

17edo with and without "h"

	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17
cents	0	71	141	212	282	353	424	494	565	635	706	776	847	918	988	1059	1129	1200
fret name	0	1a	1b	2	3	h4	4	5	6a	6b	7	8	8h	9	10	11a	11b	12
						4a	4b					8a	8b
markings		|_____|			*	|_____|		*	|_____|		*	|_____|		*		|_____|		* *

22edo with and without "h"

	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20	21	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 name	0	h1	1	2a	2b	3a	3b	4a	4b	5	5h	6	h7	7	8a	8b	9a	9b	10a	10b	11	11h	12
		1a	1b							5a	5b	6	7a	7b							11a	11b
markings		|_____|		|_____|		|*_____|		|_____|		|*_____|			|_____*|		|_____|		|_____*|		|_____|		|_____|		* *

24edo with and without "h", two ways

	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
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	0a	1	1a	2	2a	3	3a	4	4a	5	5a	6	6a	7	7a	8	8a	9	9a	10	10a	11	11a	12
markings			|_____|		|_____|		|*____|		|_____|		|*____|		|_____|		|*____|		|_____|		|*____|		|______|		|______|		**
fret	0	h1	1	h2	2	h3	3	h4	4	h5	5	h6	6	h7	7	h8	8	h9	9	h10	10	h11	11	h12	12
	0	1a	1	2a	2	3a	3	4a	4	5a	5	6a	6	7a	7	8a	8	9a	9	10a	10	11a	11	12a	12
markings		|_____|		|_____|		|____*|		|_____|		|____*|		|_____|		|____*|		|_____|		|____*|		|______|		|______|		|_____**

31edo with and without "h"

	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	25	26	27	28	29	30	31
cents	0	39	77	116	155	194	232	271	310	348	387	426	465	503	542	581	619	658	697	735	774	813	852	890	929	968	1006	1045	1084	1123	1161	1200
fret	0	0c	1a	1b	2a	2b	2c	3a	3b	3c	4a	4b	5a	5b	5c	6a	6b	7a	7b	7c	8a	8b	9a	9b	9c	10a	10b	10c	11a	11b	12a	12
					h2	2a	2b			3h													h9	9a	9b			10h
markings			|_____|		|__________|			|____*_____|			|_____|		|____*_____|			|_____|		|____*_____|			|_____|		|____*_____|			|___________|			|______|		|_____**

DFN was devised by Kite Giedraitis in November 2026. See also KDF fret numbering for the Kite guitar.