The Radioactive Decay Calculator is available with a 15-day free trial following email verification. It calculates the remaining radioactive activity using the physical half-life, initial activity and elapsed decay time.
Users can select a supplied radionuclide preset or enter a custom half-life. The calculation can be performed using reference and target dates or a directly entered elapsed time. Optional calculations can estimate the time required to reach a specified replacement threshold and the remaining dose rate when an initial dose rate is provided.
Results remain in the selected activity unit and include the decay constant, elapsed time, decay factor, remaining activity and percentage of the initial activity remaining.
This calculator is intended for education, evaluation, planning support and independent checking. It does not model daughter-product ingrowth, biological clearance, radioactive equilibrium, shielding effects or patient-specific biokinetics. All results must be independently reviewed before professional or clinical application.
What we can provide
- 15-day free trial following email verification
- Preset radionuclide selection
- Custom radionuclide half-life entry
- Multiple half-life and elapsed-time units
- Reference-date and target-date calculation
- Direct elapsed-time calculation
- Remaining radioactive activity
- Percentage of initial activity remaining
- Radioactive decay factor
- Decay constant
- Optional replacement-threshold calculation
- Optional remaining dose-rate calculation
- Clear calculation summary
- Printable calculation result