Radioactive Decay Law Calculator
Initial Activity:
Isotope Half Life
Decay Time:
Final Activity:



Radioactive decay is the process by which an unstable atomic nucleus spontaneously loses energy by emitting ionizing particles and radiation. This decay, or loss of energy, results in an atom of one type transforming to an atom of a different type. There are three types of radioactive decays, namely alpha, beta and gamma. Radiation materials are dangerous. Exposure to radiation may cause genetic mutations leading to diseases like cancer.

Radioactive Decay Law formula is:
  N = N0e-(0.693t/T1/2)
Where:
N: Activity at time 0
N0: Initial activity
t: decay time
T1/2: half time of the radioactive material

The calculation assumes that 1 year = 365 days, and 1 month = 30 days.



Isotope Half Life Table
Name
Symbol
Half Life
Unit
Actinium 227
Ac-227
21.77
Year
Aluminum 26
Al-26
720000
Year
Aluminum 29
Al-29
0.11
Hour
Americium 241
Am-241
432
Year
Antimony 124
Sb-124
60.2
Day
Arsenic 74
As-74
17.9
Day
Astatine 211
At-211
7.21
Hour
Barium 128
Ba-128
2.43
Day
Barium 133
Ba-133
10.5
Year
Barium 140
Ba-140
12.8
Day
Beryllium 7
Be-7
53.3
Day
Bismuth 207
Bi-207
38
Year
Bismuth 210
Bi-210
5.01
Day
Bromine 77
Br-77
57
Hour
Bromine 82
Br-82
35.34
Hour
Cadmium 109
Cd-109
453
Day
Calcium 45
Ca-45
162.61
Day
Carbon 11
C-11
0.34
Hour
Carbon 14
C-14
5730
Year
Cerium 141
Ce-141
32.5
Day
Cerium 144
Ce-144
284
Day
Cesium 134
Cs-134
2.06
Year
Cesium 137
Cs-137
30.17
Year
Chlorine 36
Cl-36
301000
Year
Chromium 51
Cr-51
27.7
Day
Cobalt 57
Co-57
270
Day
Cobalt 58
Co-58
71.3
Day
Cobalt 60
Co-60
5.272
Year
Copper 61
Cu-61
3.32
Hour
Copper 62
Cu-62
0.163
Hour
Copper 64
Cu-64
12.7
Hour
Copper 67
Cu-67
61.88
Hour
Curium 244
Cm-244
18.12
Year
Europium 152
Eu-152
13
Year
Fluorine 18
F-18
1.83
Hour
Gadolinium 153
Gd-153
242
Day
Gallium 67
Ga-67
78.2
Hour
Germanium 68
Ge-68
275
Day
Gold 198
Au-198
2.696
Day
Hafnium 181
Hf-181
42.5
Day
Hydrogen 3
H-3
12.26
Year
Indium 111
In-111
2.81
Day
Indium 113m
In-113m
1.66
Hour
Indium 114m
In-114m
49.51
Day
Iodine 123
I-123
13.3
Hour
Iodine 125
I-125
60.2
Day
Iodine 131
I-131
8.04
Day
Iodine 132
I-132
2.26
Hour
Iridium 192
Ir-192
74.2
Day
Iron 52
Fe-52
8.2
Hour
Iron 55
Fe-55
2.73
Year
Iron 59
Fe-59
44.6
Day
Krypton 85
Kr-85
10.72
Year
Lanthanum 140
La-140
40.3
Hour
Lutetium 177
Lu-177
6.71
Day
Lead 210
Pb-210
22.3
Year
Manganese 52m
Mn-52m
0.352
Hour
Manganese 54
Mn-54
313
Day
Manganese 56
Mn-56
2.578
Hour
Mercury 197
Hg-197
65
Hour
Mercury 203
Hg-203
46.8
Day
Molybdenum 99
Mo-99
66.02
Hour
Neodymium 147
Nd-147
11.1
Day
Neptunium 237
Np-237
2140000
Year
Nickel 63
Ni-63
100.1
Year
Niobium 94
Nb-94
20000
Year
Niobium 95
Nb-95
35.15
Day
Nitrogen 13
N-13
0.166
Hour
Oxygen 15
O-15
0.03417
Hour
Phosphorus 32
P-32
14.26
Day
Phosphorus 33
P-33
25.34
Day
Polonium 208
Po-208
2.9
Year
Polonium 210
Po-210
138
Day
Potassium 38
K-38
0.1285
Hour
Potassium 42
K-42
12.36
Hour
Promethium 147
Pm-147
2.62
Year
Plutonium 238
Pu-238
87.75
Year
Plutonium 239
Pu-239
24100
Year
Plutonium 240
Pu-240
6540
Year
Plutonium 242
Pu-242
380000
Year
Radium 226
Ra-226
1600
Year
Rubidium 82
Rb-82
0.0208
Hour
Rubidium 86
Rb-86
18.7
Day
Rubidium 87
Rb-87
4.75E10
Year
Ruthenium 103
Ru-103
39.5
Day
Ruthenium 106
Ru-106
367
Day
Scandium 46
Sc-46
83.8
Day
Selenium 75
Se-75
118.5
Day
Silver 110
Ag-110
252
Day
Silver 111
Ag-111
7.45
Day
Sodium 22
Na-22
2.602
Year
Sodium 24
Na-24
15.02
Hour
Strontium 82
Sr-82
25
Day
Strontium 83
Sr-83
1.35
Day
Strontium 85
Sr-85
64
Day
Strontium 89
Sr-89
52.7
Day
Strontium 90
Sr-90
28.8
Year
Sulphur 35
S-35
87.2
Day
Technetium 99m
Tc-99m
6.05
Hour
Technetium 99
Tc-99
213000
Year
Thallium 201
Tl-201
72.9
Hour
Thallium 204
Tl-204
3.77
Year
Thorium 228
Th-228
1.913
Year
Thorium 229
Th-229
7340
Year
Thorium 230
Th-230
77000
Year
Thorium 232
Th-232
14000000000
Year
Tin 113
Sn-113
115
Day
Tin 119m
Sn-119m
250
Day
Uranium 233
U-233
159000
Year
Uranium 234
U-234
244000
Year
Uranium 235
U-235
704000000
Year
Uranium 236
U-236
23400000
Year
Uranium 238
U-238
4470000000
Year
Vanadium 48
V-48
16
Day
Xenon 133
Xe-133
5.25
Day
Xenon 135
Xe-135
9.1
Hour
Yttrium 87
Y-87
80
Hour
Yttrium 90
Y-90
64
Hour
Zinc 62
Zn-62
9.13
Hour
Zinc 65
Zn-65
244.1
Day
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