ClarityHow to use this tool
- Enter area to cover, rainfall, collection efficiency.
- Select Calculate to view the result.
- Check the method and assumptions below before using the result.
Input reference and sample values
Use the units and choices shown for each field. Sample values are provided for practice, not as recommendations.
| Input | Format and units | Sample |
|---|---|---|
| Area to cover | Numeric value. Unit: m². Must be greater than zero. | 20 |
| Rainfall | Numeric value. Unit: mm. Zero or positive. | 20 |
| Collection efficiency | Numeric value. Unit: %. Zero or positive. Maximum: 100. | 80 |
Result for these sample inputs
320 L
Select Try the example in the form to load these values and calculate them again. This replaces the current form inputs. Compare the result with the method and worked explanation below.
The method, explained
Liters = roof plan area × rainfall(mm) × efficiency/100.
Using area to cover = 20 m², rainfall = 20 mm, collection efficiency = 80 %, the result is 320 L. Change these example inputs to match your task; use the method above to check each step.
What to keep in mind
Does not assess water quality or storage overflow. A material-quantity estimate, not a structural design or building-code check. Confirm site measurements, supplier coverage and waste before ordering.
Methodology maintained by ClarityKit. How these tools are built and checked.