What is this calculator?
Estimate remaining quantity after exponential decay.
What can you use it for?
Use it when solving an exercise, checking a result, or working with the particular quantities shown in this form. Estimate remaining quantity after exponential decay.
How to use it
- Enter initial quantity.
- Enter half-life.
- Enter elapsed time.
- Select Calculate (or Generate for random tools).
- Read the answer and any additional results below the form. Check the units and the limits of the method.
Formula and method
Result = initial quantity × 0.5^(elapsed time/half-life)
The formula uses the units and definitions shown above. Each input is substituted before the arithmetic is evaluated; the calculated output is rounded for display.
Worked example
Initial quantity: 100, Half-life: 10, Elapsed time: 30. The result is 12.5 (result).
Assumptions and limits
Half-life and elapsed time must use the same unit.
Frequently asked questions
What inputs does the Half-Life Calculator need?
Use initial quantity, half-life, elapsed time. Read the answer and any additional results below the form. Check the units and the limits of the method.
What assumptions apply to the Half-Life Calculator?
Half-life and elapsed time must use the same unit.