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Chemistry Fundamentals Program

Nuclear Decay Calculator

Use this calculator to investigate how a unstable substance decays over time. The first two equations are found in the Nuclear Chemistry section.

From the above two equations, we derive the following, which we use as the mathematical basis for calculating decay.

Here, t1/2 is the half-life of the element, which is specific to each element. By selecting an element from the table below, you are specifying the half life that appears in the table. You also must enter an initial number of moles of nuclei, and the amount of time that you would like to consider. Note that you must also select the appropriate units of time.
Element Half-life Element Half-life
Uranium-238 4.4x109 years Carbon-14 5.73x103 years
Potassium-40 1.3x109 years Phosphorus-32 14.28 days
Uranium-235 7.1x108 years Magnesium-27 9.46 minutes
Iodine-129 1.7x107 years Magnesium-20 0.6 seconds

Any scientific notation should be entered in the form (XeY) where "eY" represents multiplying by 10Y
(e.g. 1.09*105 equals 1.09e5)

Element Initial Number of moles of Nuclei Time Period ()

After moles of nuclei remain.

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in cooperation with the Department of Chemistry,
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