What this calculator does
Bacterial/cell growth (doubling time) works out population size after exponential growth at a fixed doubling time. 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
FormulaN = N₀ × 2^(t/td); k = ln2 / td
The inputs explained
| Field | What to enter |
|---|---|
| Initial population (cells) | A number, measured in cells. Starts at 100. |
| Doubling time (min) | A number, measured in min. Starts at 20. |
| Elapsed time (min) | A number, measured in min. Starts at 60. |
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 initial population
Every other input is held at the calculator’s starting values while initial population varies. Select any row to load that scenario into the calculator.
How the answer changes with initial population