Half-Life Calculator
Calculate remaining quantity after radioactive or exponential decay from half-life and elapsed time, plus decay constant and mean lifetime.
N(t) = N₀ × (1/2)t / t½. Common half-lives: Carbon-14 ≈ 5,730 years, Iodine-131 ≈ 8.02 days, Caesium-137 ≈ 30.1 years.
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How to Use
Enter the initial quantity, the half-life and the elapsed time in the same unit. Results update as you type.
Disclaimer: This tool is provided "as is" without warranty of any kind. Results are for educational and utility purposes.
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