Beta Decay Calculator

Beta decay is the process by which a radioactive isotope loses activity over time — the Beta Decay Calculator tracks how much radioactivity remains in a sample after a given period. Select an isotope (or enter a custom one), set its half-life, initial activity, and time elapsed to get the final activity, along with the decay constant, percent remaining, percent decayed, and half-lives elapsed.

days

Half-life in days

Results

Final Activity

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Decay Constant

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Percent Remaining

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Percent Decayed

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Half-Lives Elapsed

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Frequently Asked Questions

What is beta decay and how is it calculated?

Beta decay is a type of radioactive decay where a beta particle (electron or positron) is emitted from an atomic nucleus. The calculation uses the exponential decay formula: A(t) = A₀ × e^(-λt), where A(t) is activity at time t, A₀ is initial activity, and λ is the decay constant.

How do I find the half-life of an isotope?

Half-life values are well-documented constants for each isotope. You can find them in nuclear data tables or by selecting a common isotope from our dropdown menu, which automatically populates the half-life value.

What units can I use for radioactive activity?

Our calculator supports both SI units (Becquerel and its multiples) and traditional units (Curie and its multiples). 1 Curie = 3.7 × 10¹⁰ Becquerels.

How accurate are the decay calculations?

The calculations use standard nuclear physics formulas and are accurate for typical decay scenarios. However, results should be independently verified for critical applications, especially in medical or industrial settings.

Can I calculate decay for custom isotopes?

Yes, select 'Custom Isotope' and enter the half-life manually. Ensure you use reliable nuclear data sources for the half-life value to get accurate results.

What is the decay constant and how is it related to half-life?

The decay constant (λ) represents the probability of decay per unit time. It's related to half-life by λ = ln(2)/T₁/₂, where T₁/₂ is the half-life period.

How do I convert between different time units?

The calculator automatically handles time unit conversions. Simply select your preferred time unit from the dropdown, and all calculations will be performed correctly using the appropriate conversion factors.