Science CalculatorsPrivate by design
Half-Life Calculator
Enter an initial amount, half-life, and elapsed time to calculate how much remains after decay.
How to use this tool
- 1Enter the initial amount.
- 2Enter the half-life.
- 3Enter the elapsed time (same units as half-life).
- 4See the remaining amount and percentage.
Frequently asked questions
Does this only apply to radioactivity?+
No — the same exponential decay math applies to drug elimination, capacitor discharge, and any process where a quantity halves at a constant rate.
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