Radioactive Decay Calculator

Use Radioactive Decay Calculator to obtain the exact radioactive decay or half-life of the isotope easily. All you have to do is enter the isotope name and initial activity, decay time and half-life details to get the final activity value.

Choose a Calculation
Initial Quantity(A0)
Half-life time (T1/2)
Decay Time(t)
Final activity(A)

Half-Life Radioactive Decay Calculator: Want to calculate the radioactive decay of a substance in an easy way? Then you must check out this page. Here, we are offering simple steps to solve the half-life and radioactive decay of the substance. Read on to know the radioactive decay definition, formula. Also, get the example questions with solutions for a better understanding of the concept.

Steps to Calculate Radioactive Decay

Go through the step by step procedure to find the radioactive decay and half-life of the substance.

  • Provide the isotope name as input and press the calculate button.
  • You can see isotope half-life, mean lifetime, decay constant, specific activity and decay modes.
  • Get initial activity, decay time, and half-life
  • Divide the decay time by half-life.
  • Multiply the result with -0.693.
  • Find the exponential of the result.
  • Multiply the obtained result with the initial activity to know the final activity value.

What is Radioactive Decay?

Radioactivity is the phenomenon exhibited by the nuclei of an atom as a result of nuclear instability. The radioactive decay is defined as the spontaneous breakdown of the nucleus, that results in the release of energy and also the matter from the atomic nucleus. The radio isotopes do not have enough binding energy to hold the nucleus in the atom.

The three important types of radioactive decay are Alpha decay, Beta decay and Gamma decay.

  1. Alpha Decay: The process of alpha particle emitting its necleus is the alpha decay. The formuls is E = (mi - mf - p)c2
  2. Beta Decay: A beta particle is also called an electron. If the reaction involves electrons nucleus shed out neutrons one by one.
  3. Gamma Decay: The nucleus has orbiting electrons which have some energy, when an electron jumps from a level of high energy to low energy, there is an emission of a photon. Whenever it rearranges into a low energy level, a high energy photon is shooted out which is called the gamma-ray.

Radioactive Decay Equation

The radioactive decay formula is A = A0 e-0.693t/T½


A is the final activity

A0 is the initial activity

t is the decay time

T½ is the half-life


Question: If the initial activity is 100, half-life is 15 seconds, and decay time is 10. Find the final activity?


Given that,

initial Activity A0 = 100

Decay time t = 10

Half-life T½ = 15

Final activity is A = A0 e-0.693t/T½

A = 100 e-0.693 * 10/15

= 63.002

Therefore, final activity is 63.002

If you would like to learn more about the other chemical calculator that gives instant results, stay tuned to Chemistrycalc.Com


Frequently Asked Question’s on Radioactive Decay Calculator

1. How to calculate radioactive decay?

The steps to find the radioactive decay are given here. Divide the decay time by the half-life, multiply the result with -0.693. Get the exponential of the product and multiply it with the initial activity to obtain the final activity.

2. What is meant by radioactive decay?

Radioactive decay is defined as the spontaneous breakdown of the nucleus, that results in the release of energy and also the matter from the atomic nucleus.

3. What are the 5 types of radioactive decay?

The 5 different types of radioactive decay are alpha decay, beta decay, gamma emission, positron emission (β+ decay), and electron capture.

4. What is the radioactive decay formula?

The radiocative decay formula is A = A0 e-0.693t/T½.