What this calculator does
Radioactive activity (Bq / Ci) works out decay rate of a radioactive sample from its amount and half-life, in becquerels and curies. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
The inputs explained
| Field | What to enter |
|---|---|
| Amount of substance (mol) | A number, measured in mol. Starts at 0.001. |
| Half-life (years) | A number, measured in years. Starts at 5730. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with amount of substance
Every other input is held at the calculator’s starting values while amount of substance varies. Select any row to load that scenario into the calculator.