Half-Life Calculator

Fast, free, accurate and 100% private. Works on any device.

Half-Life Calculator

Enter your values below and click the button for instant results.

Half-Life Calculations

Initial Amount

Remaining Amount

Time Elapsed (any unit)

Result

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About Half-Life Calculator

This Half-Life Calculator is fast, accurate and 100% private. All calculations run locally in your browser, so your information never leaves your device. No sign-up, no downloads, works beautifully on mobile and desktop.

FAQ

What is half-life?▶

Half-life is the time taken for half of a radioactive substance (or any decaying quantity) to decay or disintegrate.

How is half-life calculated from remaining amount?▶

Use the exponential decay formula: t(1/2) = (time * ln(2)) / ln(initial / remaining).