Radioactive Decay Calculators

Calculator #1
 
Given the half life and initial radioactivity, this first calculator works out the radioactivity remaining after a specified time.  The decay constant is also calculated.


Enter numbers in the relevant boxes and click the Calculate Remaining Radioactivity button to view results below.
Half Life (hours)
Initial Radioactivity (Bq)
Time (hours)



The radioactivity remaining after  hours is:  Bq
which is equal to  percent of the initial radioactivity.
The decay constant is  per hour.


Calculator #2

Given the initial radioactivity and the radioactivity remaining after a specified time, this second calculator works out the half life and the decay constant.


Enter numbers in the relevant boxes and click the Calculate Half Life button to view results below.

Initial Radioactivity (Bq)
Final Radioactivity (Bq)
Time (hours)




The half life is  hours
and the decay constant is  per hour.