Half-Life Calculator

Calculate any parameter in radioactive decay equations

What to Calculate:

Time Unit:

Initial Amount (N₀):

Half-Life (years):

Elapsed Time (years):

Common Isotopes:

Decay Law: N(t) = N₀ × (1/2)^(t/t₁/₂) = N₀ × e^(-lambda×t)

Half-Life: t₁/₂ = ln(2)/lambda = t × ln(2)/ln(N₀/N)

Time: t = t₁/₂ × ln(N₀/N) / ln(2)

Initial: N₀ = N × 2^(t/t₁/₂)

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MyCalcBuddy Editorial Team

This page is maintained as an educational calculator reference.

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Formula Source: University Physics

by Young & Freedman

ðŸ”„Last reviewed: May 2026

âœ“Formula checks are based on standard references and internal QA review.