Natural holmium (67Ho) contains one observationally stable isotope, 165Ho. The below table lists 36 isotopes spanning 140Ho through 175Ho as well as 33 nuclear isomers. Among the known synthetic radioactive isotopes; the most stable one is 163Ho, with a half-life of 4,570 years. All other radioisotopes have half-lives not greater than 1.117 days in their ground states (although the metastable 166m1Ho has a half-life of about 1,200 years), and most have half-lives under 3 hours.
|-| 140Ho| style="text-align:right" | 67| style="text-align:right" | 73| 139.96854(54)#| 6(3) ms||| 8+#| |-| 141Ho| style="text-align:right" | 67| style="text-align:right" | 74| 140.96310(54)#| 4.1(3) ms||| (7/2−)| |-| style="text-indent:1em" | 141mHo| colspan="3" style="text-indent:2em" | 66(2) keV| 6.4(8) μs||| (1/2+)||-| rowspan=2|142Ho| rowspan=2 style="text-align:right" | 67| rowspan=2 style="text-align:right" | 75| rowspan=2|141.95977(54)#| rowspan=2|400(100) ms| β+| 142Dy| rowspan=2|(6 to 9)| rowspan=2||-| p| 141Dy|- | 143Ho| style="text-align:right" | 67| style="text-align:right" | 76| 142.95461(43)#| 300# ms
[>200 ns]| β+| 143Dy| 11/2−#||-| rowspan=2|144Ho| rowspan=2 style="text-align:right" | 67| rowspan=2 style="text-align:right" | 77| rowspan=2|143.95148(32)#| rowspan=2|0.7(1) s| β+| 144Dy| rowspan=2|| rowspan=2||-| β+, p| 143Tb|-| 145Ho| style="text-align:right" | 67| style="text-align:right" | 78| 144.94720(32)#| 2.4(1) s| β+| 145Dy| (11/2−)||-| style="text-indent:1em" | 145mHo| colspan="3" style="text-indent:2em" | 100(100)# keV| 100# ms||| 5/2+#||-| rowspan=2|146Ho| rowspan=2 style="text-align:right" | 67| rowspan=2 style="text-align:right" | 79| rowspan=2|145.94464(21)#| rowspan=2|3.6(3) s| β+| 146Dy| rowspan=2|(10+)| rowspan=2||-| β+, p (rare)| 145Tb|-| rowspan=2|147Ho| rowspan=2 style="text-align:right" | 67| rowspan=2 style="text-align:right" | 80| rowspan=2|146.94006(3)| rowspan=2|5.8(4) s| β+| 147Dy| rowspan=2|(11/2−)| rowspan=2||-| β+, p (rare)| 146Tb|-| 148Ho| style="text-align:right" | 67| style="text-align:right" | 81| 147.93772(14)| 2.2(11) s| β+| 148Dy| (1+)| |-| rowspan=2 style="text-indent:1em" | 148m1Ho| rowspan=2 colspan="3" style="text-indent:2em" | 400(100)# keV| rowspan=2|9.49(12) s| β+ (99.92%)| 148Dy| rowspan=2|(6)−| rowspan=2||-| β+, p (.08%)| 147Tb|-| style="text-indent:1em" | 148m2Ho| colspan="3" style="text-indent:2em" | 690(100)# keV| 2.35(4) ms||| (10+)||-| 149Ho| style="text-align:right" | 67| style="text-align:right" | 82| 148.933775(20)| 21.1(2) s| β+| 149Dy| (11/2−)||-| style="text-indent:1em" | 149m1Ho| colspan="3" style="text-indent:2em" | 48.80(20) keV| 56(3) s| β+| 149Dy| (1/2+)||-| style="text-indent:1em" | 149m2Ho| colspan="3" style="text-indent:2em" | 7200(350) keV| >=100 ns|||||-| 150Ho| style="text-align:right" | 67| style="text-align:right" | 83| 149.933496(15)| 76.8(18) s| β+| 150Dy| 2−||-| style="text-indent:1em" | 150m1Ho| colspan="3" style="text-indent:2em" | −10(50) keV| 23.3(3) s| β+| 150Dy| (9)+||-| style="text-indent:1em" | 150m2Ho| colspan="3" style="text-indent:2em" | ~8000 keV| 751 ns|||||-| rowspan=2|151Ho| rowspan=2 style="text-align:right" | 67| rowspan=2 style="text-align:right" | 84| rowspan=2|150.931688(13)| rowspan=2|35.2(1) s| β+ (78%)| 151Dy| rowspan=2|11/2(−)| rowspan=2||-| α (22%)| 147Tb|-| rowspan=2 style="text-indent:1em" | 151mHo| rowspan=2 colspan="3" style="text-indent:2em" | 41.0(2) keV| rowspan=2|47.2(10) s| α (77%)| 147Tb| rowspan=2|1/2(+)| rowspan=2||-| β+ (22%)| 151Dy|-| rowspan=2|152Ho| rowspan=2 style="text-align:right" | 67| rowspan=2 style="text-align:right" | 85| rowspan=2|151.931714(15)| rowspan=2|161.8(3) s| β+ (88%)| 152Dy| rowspan=2|2−| rowspan=2||-| α (12%)| 148Tb|-| style="text-indent:1em" | 152m1Ho| colspan="3" style="text-indent:2em" | 160(1) keV| 50.0(4) s||| 9+||-| style="text-indent:1em" | 152m2Ho| colspan="3" style="text-indent:2em" | 3019.59(19) keV| 8.4(3) μs||| 19−||-| rowspan=2|153Ho| rowspan=2 style="text-align:right" | 67| rowspan=2 style="text-align:right" | 86| rowspan=2|152.930199(6)| rowspan=2|2.01(3) min| β+ (99.94%)| 153Dy| rowspan=2|11/2−| rowspan=2||-| α (.05%)| 149Tb|-| rowspan=2 style="text-indent:1em" | 153m1Ho| rowspan=2 colspan="3" style="text-indent:2em" | 68.7(3) keV| rowspan=2|9.3(5) min| β+ (99.82%)| 153Dy| rowspan=2|1/2+| rowspan=2||-| α (.18%)| 149Tb|-| style="text-indent:1em" | 153m2Ho| colspan="3" style="text-indent:2em" | 2772 keV| 229(2) ns||| (31/2+)||-| rowspan=2|154Ho| rowspan=2 style="text-align:right" | 67| rowspan=2 style="text-align:right" | 87| rowspan=2|153.930602(9)| rowspan=2|11.76(19) min| β+ (99.98%)| 154Dy| rowspan=2|2−| rowspan=2||-| α (.02%)| 150Tb|-| rowspan=3 style="text-indent:1em" | 154mHo| rowspan=3 colspan="3" style="text-indent:2em" | 238(30) keV| rowspan=3|3.10(14) min| β+ (99.99%)| 154Dy| rowspan=3|8+| rowspan=3||-| α (.001%)| 150Tb|-| IT (rare)| 154Ho|-| 155Ho| style="text-align:right" | 67| style="text-align:right" | 88| 154.929103(19)| 48(1) min| β+| 155Dy| 5/2+||-| style="text-indent:1em" | 155mHo| colspan="3" style="text-indent:2em" | 141.97(11) keV| 880(80) μs||| 11/2−||-| 156Ho| style="text-align:right" | 67| style="text-align:right" | 89| 155.92984(5)| 56(1) min| β+| 156Dy| 4−||-| rowspan=2 style="text-indent:1em" | 156m1Ho| rowspan=2 colspan="3" style="text-indent:2em" | 100(50)# keV| rowspan=2|7.8(3) min| β+| 156Dy| rowspan=2|(9+)| rowspan=2| |-| IT| 156Ho|-| style="text-indent:1em" | 156m2Ho| colspan="3" style="text-indent:2em" | 52.4(5) keV| 9.5(15) s||| 1−||-| 157Ho| style="text-align:right" | 67| style="text-align:right" | 90| 156.928256(26)| 12.6(2) min| β+| 157Dy| 7/2−||-| rowspan=2|158Ho| rowspan=2 style="text-align:right" | 67| rowspan=2 style="text-align:right" | 91| rowspan=2|157.928941(29)| rowspan=2|11.3(4) min| β+ (93%)| 158Dy| rowspan=2|5+| rowspan=2||-| α (7%)| 154Tb|-| rowspan=2 style="text-indent:1em" | 158m1Ho| rowspan=2 colspan="3" style="text-indent:2em" | 67.200(10) keV| rowspan=2|28(2) min| IT (81%)| 158Ho| rowspan=2|2−| rowspan=2||-| β+ (19%)| 158Dy|-| style="text-indent:1em" | 158m2Ho| colspan="3" style="text-indent:2em" | 180(70)# keV| 21.3(23) min||| (9+)||-| 159Ho| style="text-align:right" | 67| style="text-align:right" | 92| 158.927712(4)| 33.05(11) min| β+| 159Dy| 7/2−||-| style="text-indent:1em" | 159mHo| colspan="3" style="text-indent:2em" | 205.91(5) keV| 8.30(8) s| IT| 159Ho| 1/2+||-| 160Ho| style="text-align:right" | 67| style="text-align:right" | 93| 159.928729(16)| 25.6(3) min| β+| 160Dy| 5+||-| rowspan=2 style="text-indent:1em" | 160m1Ho| rowspan=2 colspan="3" style="text-indent:2em" | 59.98(3) keV| rowspan=2|5.02(5) h| IT (65%)| 160Ho| rowspan=2|2−| rowspan=2||-| β+ (35%)| 160Dy|-| style="text-indent:1em" | 160m2Ho| colspan="3" style="text-indent:2em" | 197(16) keV| 3 s||| (9+)||-| 161Ho| style="text-align:right" | 67| style="text-align:right" | 94| 160.927855(3)| 2.48(5) h| EC| 161Dy| 7/2−||-| style="text-indent:1em" | 161mHo| colspan="3" style="text-indent:2em" | 211.16(3) keV| 6.76(7) s| IT| 161Ho| 1/2+||-| 162Ho| style="text-align:right" | 67| style="text-align:right" | 95| 161.929096(4)| 15.0(10) min| β+| 162Dy| 1+||-| rowspan=2 style="text-indent:1em" | 162mHo| rowspan=2 colspan="3" style="text-indent:2em" | 106(7) keV| rowspan=2|67.0(7) min| IT (62%)| 162Ho| rowspan=2|6−| rowspan=2||-| β+ (38%)| 162Dy|-| 163Ho| style="text-align:right" | 67| style="text-align:right" | 96| 162.9287339(27)| 4570(25) y| EC| 163Dy| 7/2−||-| style="text-indent:1em" | 163mHo| colspan="3" style="text-indent:2em" | 297.88(7) keV| 1.09(3) s| IT| 163Ho| 1/2+||-| rowspan=2|164Ho| rowspan=2 style="text-align:right" | 67| rowspan=2 style="text-align:right" | 97| rowspan=2|163.9302335(30)| rowspan=2|29(1) min| EC (60%)| 164Dy| rowspan=2|1+| rowspan=2||-| β− (40%)| 164Er|-| style="text-indent:1em" | 164mHo| colspan="3" style="text-indent:2em" | 139.77(8) keV| 38.0(10) min
[37.5(+15−5) min]| IT| 164Ho| 6−||-| 165Ho| style="text-align:right" | 67| style="text-align:right" | 98| 164.9303221(27)| colspan=3 align=center|Observationally Stable[1] | 7/2−| 1.0000|-| 166Ho| style="text-align:right" | 67| style="text-align:right" | 99| 165.9322842(27)| 26.83(2) h| β−| 166Er| 0−||-| style="text-indent:1em" | 166m1Ho| colspan="3" style="text-indent:2em" | 5.985(18) keV| 1200(180) y| β−| 166Er| (7)−||-| style="text-indent:1em" | 166m2Ho| colspan="3" style="text-indent:2em" | 190.9052(20) keV| 185(15) μs||| 3+||-| 167Ho| style="text-align:right" | 67| style="text-align:right" | 100| 166.933133(6)| 3.003(18) h| β−| 167Er| 7/2−||-| style="text-indent:1em" | 167mHo| colspan="3" style="text-indent:2em" | 259.34(11) keV| 6.0(10) μs||| 3/2+||-| 168Ho| style="text-align:right" | 67| style="text-align:right" | 101| 167.93552(3)| 2.99(7) min| β−| 168Er| 3+||-| rowspan=2 style="text-indent:1em" | 168m1Ho| rowspan=2 colspan="3" style="text-indent:2em" | 59(1) keV| rowspan=2|132(4) s| IT (99.5%)| 168Ho| rowspan=2|(6+)| rowspan=2||-| β− (.5%)| 168Er|-| style="text-indent:1em" | 168m2Ho| colspan="3" style="text-indent:2em" | 143.4(2) keV| >4 μs||| (1)−||-| style="text-indent:1em" | 168m3Ho| colspan="3" style="text-indent:2em" | 192.6(2) keV| 108(11) ns||| 1+||-| 169Ho| style="text-align:right" | 67| style="text-align:right" | 102| 168.936872(22)| 4.72(10) min| β−| 169Er| 7/2−||-| 170Ho| style="text-align:right" | 67| style="text-align:right" | 103| 169.93962(5)| 2.76(5) min| β−| 170Er| 6+#||-| style="text-indent:1em" | 170mHo| colspan="3" style="text-indent:2em" | 120(70) keV| 43(2) s| β−| 170Er| (1+)||-| 171Ho| style="text-align:right" | 67| style="text-align:right" | 104| 170.94147(64)| 53(2) s| β−| 171Er| 7/2−#||-| 172Ho| style="text-align:right" | 67| style="text-align:right" | 105| 171.94482(43)#| 25(3) s| β−| 172Er|||-| 173Ho| style="text-align:right" | 67| style="text-align:right" | 106| 172.94729(43)#| 10# s| β−| 173Er| 7/2−#||-| 174Ho| style="text-align:right" | 67| style="text-align:right" | 107| 173.95115(54)#| 8# s|||||-| 175Ho| style="text-align:right" | 67| style="text-align:right" | 108| 174.95405(64)#| 5# s||| 7/2−#|