3.0 or later, or Internet Exploror 4.0.
Choose the isotope, and the half-life will be provided for you.
(Or manually enter the half-life of an isotope not on the list.)
Then enter the original amount and elapsed time to calculate
the amount of isotope remaining.
Select the isotope:
Half-life (in days):
Enter the amount of starting material (in μCi):
Enter the time elapsed (in days):