Calculator Inputs and Outputs
Inputs
- Roof collection area (sq ft) — example: 1200
- Rainfall depth (in) — example: 1
- Collection efficiency (%) — example: 85
- Barrel capacity (gal) — example: 55
Results
- Water captured (gal)
- Equivalent barrel fills (barrels)
- Water captured (L)
Formula used
One inch of rain on one square foot yields about 0.623 gallon before losses.
How to Use the Rain Barrel Capture Calculator
Enter the requested values, confirm the units and assumptions, then select Calculate Rain Barrel Capture. The default inputs provide a complete working example.
Formula
One inch of rain on one square foot yields about 0.623 gallon before losses.
Understanding the Results
The primary answer appears first. Supporting outputs provide related quantities, conversions, timing, costs, ratios, or intermediate values. The calculator keeps extra precision internally before display rounding.
Accuracy Tips
- Use measured values and consistent units.
- Review rates, timing, allowances, efficiency, and category-specific assumptions.
- Recalculate whenever a project condition changes.
Important Note
This calculator is an informational planning tool. Confirm critical financial, medical, construction, scientific, tax, legal, or safety decisions with an appropriately qualified professional.
Calculation Standards
This tool uses documented formulas and high-precision internal values. Displayed results may be rounded for readability. Review the assumptions and verify important decisions with a qualified professional.
Read our calculation methodology