What this calculator does
Bath vs. shower water use works out compares the water used filling a bath against taking a shower of a given length. 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
FormulaShower water = flow rate × duration; compared directly against the bath fill volume
The inputs explained
| Field | What to enter |
|---|---|
| Bath fill volume (L) | A number, measured in L. Starts at 150. |
| Shower flow rate (L/min) | A number, measured in L/min. Starts at 9. |
| Shower duration (min) | A number, measured in min. Starts at 8. |
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 bath fill volume
Every other input is held at the calculator’s starting values while bath fill volume varies. Select any row to load that scenario into the calculator.