Half-Life Calculator

Calculate half-life, remaining quantity, or time elapsed for radioactive decay or exponential decay processes.

Calculate *

Decay Type

Initial Quantity (N₀) *

atoms

Remaining Quantity (N) *

atoms

Time Elapsed (t) *

Time Unit

Show Steps

⚠️

Half-Life Result

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📊

Decay Visualization

Exponential decay curve with half-life markers

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📋

Calculation Breakdown

Step-by-step half-life calculation

⏱️

Half-Life (t₁/₂)

—

Time for half decay

📊

Decay Constant (λ)

—

ln(2)/t₁/₂

📐

Half-Lives Passed

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n = t/t₁/₂

📈

Remaining %

—

(N/N₀) × 100

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Half-Life Formulas

Key decay concepts

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Half-Life Tips

Understanding radioactive decay

⏱️ Scientific Disclaimer: This half-life calculator uses the exponential decay formula N = N₀·e^(−λt). Results are for educational purposes. Half-life is constant for a given isotope.