A Nuclear Community Website
Enter or Select Element
Select Isotope
Actinium (Ac)
Americium (Am)
Antimony (Sb)
Argon (Ar)
Arsenic (As)
Astatine (At)
Barium (Ba)
Beryllium (Be)
Bismuth (Bi)
Bromine (Br)
Cadmium (Cd)
Calcium (Ca)
Californium (Cf)
Carbon (C)
Cerium (Ce)
Cesium (Cs)
Chlorine (Cl)
Chromium (Cr)
Cobalt (Co)
Copper (Cu)
Curium (Cm)
Dysprosium (Dy)
Erbium (Er)
Europium (Eu)
Fluorine (F)
Gadolinium (Gd)
Gallium (Ga)
Germanium (Ge)
Gold (Au)
Holmium (Ho)
Hydrogen (H)
Indium (In)
Iodine (I)
Iridium (Ir)
Iron (Fe)
Krypton (Kr)
Lanthanium (La)
Lead (Pb)
Lutetium (Lu)
Manganese (Mn)
Molybdenum (Mo)
Neptunium (Np)
Nickel (Ni)
Niobium (Nb)
Nitrogen (N)
Osmium (Os)
Oxygen (O)
Palladium (Pd)
Phosphorous (P)
Plutonium (Pu)
Polonium (Po)
Potassium (K)
Praseodymium (Pr)
Promethium (Pm)
Protoactinium (Pa)
Radium (Ra)
Radon (Rn)
Rhenium (Re)
Rhodium (Rh)
Rubidium (Rb)
Ruthenium (Ru)
Samarium (Sm)
Scandium (Sc)
Selenium (Se)
Silver (Ag)
Sodium (Na)
Strontium (Sr)
Sulfur (S)
Tantalum (Ta)
Technectium (Tc)
Tellurium (Te)
Terbium (Tb)
Thallium (Tl)
Thorium (Th)
Thullium (Tm)
Tin (Sn)
Tungsten (W)
Uranium (U)
Xenon (Xe)
Yittrium (Y)
Ytterbium (Yb)
Zinc (Zn)
Zirconium (Zr)
Loading…
cpm
cpm
Half Life
Select Units
cpm
dpm
pCi
nCi
uCi
mCi
Ci
Bq
kBq
MBq
GBq
TBq
cpm
dpm
pCi
nCi
uCi
mCi
Ci
Bq
kBq
MBq
GBq
TBq
Calculated Activity
Original Activity
Decay Calculations
Calculation Date and/or Time
Original Date and/or Time
Isotope Not Listed?
Radioactive Decay
UK Radiation Adviser
Nuclear Links
Nuclear Jobs
MARSSIM
Nuclear Resources
US Health Physics Society
Author's Personal Website
US Health Physics Consultant
UK Radiation Protection Society
NRRPT Study Kit and Classic RP College Textbook
Rad Pro Calculator Recommends These Links
Useful for calculating today's activity for any radioactive isotope. You may also back decay sources to find out the original activity (or for any date), knowing the current activity. If the isotope that you wish to decay is not on the drop down list, check the 'not listed' check-box and manually enter the isotope name and its half-life to perform the calculation. You may enter date or time or a combination of both. Calendar pickers are included for date entry convenience.