Give rain a place to land.
Estimate how much runoff a roof creates and how much space a rain garden needs.
Site inputs
Your rain pocket
Runoff to capture3.06 m³
Recommended garden area68.0 m²
Liters to store3,060 L
How garden area affects capture (for this site)
Runoff
captured
(m³)
captured
(m³)
Garden area (m²)
Concept estimate only. Check local soil and drainage before construction.
Methodology
Simple volume balance using your inputs.
Runoff = area × rainfall × coefficient
(m³, with rainfall in meters)
Garden area = runoff ÷ (depth × void fraction)
(m², with storage layer depth in meters)
A screening tool for one rain event. It does not model infiltration rate, overflow routes, groundwater, or local design standards.