Half-life and decay constant
T½ = ln 2 / λ and λ = ln 2 / T½.
Calculator
How to use
Half-life
Use consistent time units.
Educational use only. Check signs, units, and modeling assumptions (e.g. flat Earth g, no air resistance unless stated).
T½ = ln 2 / λ and λ = ln 2 / T½.
Use consistent time units.
Educational use only. Check signs, units, and modeling assumptions (e.g. flat Earth g, no air resistance unless stated).
Model / formula
T½ = ln 2 / λ
Result
λ = 1.2097e-4 (per unit time)