Tool 511 · Exponential decay intelligence
Half‑Life Calculator
Solve any half-life variable, convert between half-life, decay constant and mean lifetime, calculate radioactive activity from sample mass, inspect milestones, or model a two-component decay mixture — all locally.
Any-variable solverN₀, N(t), t or t½ from the other three.
Activity modeAtoms, Bq, Ci, specific activity and optional decay power.
Mixture modeTwo half-lives, crossover time and instantaneous effective half-life.
Transparent mathMilestones, λ, τ, fraction decayed and plotted curves.
Solve any one decay variable
Choose the unknown and enter the other three values. Amounts can be grams, atoms, Bq, mol, concentration, or any consistent unit.
Exponential decay
Half-life ↔ decay constant ↔ mean lifetime
For λ, the selected time basis means “per selected unit” (for example, day⁻¹). For t½ and τ it is the time unit itself.
Radioactive sample activity
Activity is computed from A = λN. Molar mass must correspond to the isotope/sample basis you intend. Optional power assumes the entered energy is deposited per decay; real detectable/deposited energy can differ.