Half-Life Calculator
Find the remaining amount of a radioactive isotope after a given time using N(t) = N₀ × (1/2)^(t/t½). Click any isotope to pre-fill its half-life.
Common Isotopes (click to use)
Carbon-145,730 years
Radium-2261,600 years
Iodine-1318.02 days
Uranium-2384.47 billion years
Phosphorus-3214.3 days
Tritium (H-3)12.3 years