basic

Radioactive Decay Activity Calculator

A = A₀·e^(−λt) — activity vs time from decay constant.

Calculates radioactive activity at any elapsed time from initial activity and decay constant or half-life. Returns activity in Becquerels and Curies.

Dr. Helena Ortiz By Dr. Helena Ortiz
Published Last reviewed 1 min read

Inputs

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

λ = ln2/t½; A(t) = A₀ × e^(−λt)

In depth

Calculates radioactive activity at any elapsed time from initial activity and decay constant or half-life. Returns activity in Becquerels and Curies.