Radioactive Decay Constant Calculator

Calculate decay constant from half-life, mean lifetime, or activity

Calculation Method:

Time Unit:

Half-Life (seconds):

Common Isotopes:

From Half-Life: lambda = ln(2) / t_1/2 = 0.693 / t_1/2

From Mean Lifetime: lambda = 1 / tau

From Activity: lambda = A / N

Relationship: tau = 1/lambda = t_1/2 / ln(2) ≈ 1.443 × t_1/2

The decay constant represents the probability per unit time that a nucleus will decay.