Radioactive Decay Calculator

Radioactive decay is the spontaneous transformation of unstable atomic nuclei over time. The half-life is the time for half the atoms to decay; after n half-lives, N₀/2ⁿ atoms remain

The calculator uses the standard published formula for radioactive decay. Results are accurate to the precision of the inputs you provide. For financial, medical, or legal decisions, always verify with a qualified professional.

This calculator works with inches, percentages. You can enter values in the units shown — the calculator handles all conversions internally.

The core formula is: N(t) = N₀ × (½)^(t/t½). Each step in the calculation is shown so you can verify the result manually.