# Calculate Garden Soil Volume and Rainwater Collection
A raised bed soil calculator answers one practical question: how many liters of substrate will fill the growing space? A rainwater collection calculator answers another: how much water could a roof, awning, or balcony catch during a rainfall event? This planner puts both estimates side by side for small gardens, containers, balconies, and community plots. # Raised Bed Soil Volume Formula
Soil volume is calculated locally with area in square meters × depth in centimeters × 10 = liters of substrate. For example, a 12 m² bed at 30 cm deep needs 3,600 liters before settling, drainage layers, or any planting design changes. -
Growing area: the bed, balcony, or planter footprint.
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Substrate depth: the soil layer you plan to fill.
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Collection area: the roof, awning, or surface feeding the vessel.
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Rainfall event: the rainfall depth you want to model in millimeters.
# Rainwater Collection Estimate
The water estimate starts with collection area × rainfall, then keeps 85 percent for runoff and 90 percent after collection losses. One liter spread over one square meter equals one millimeter of water, which makes the result easy to compare with the growing area. # Compare Garden Scenarios Offline
Try a balcony shower, a raised bed, and a community plot with the quick presets, then replace them with your measurements. The planner does not use an address, map, forecast, or official climate dataset. It stays in the browser so you can test assumptions before buying substrate or a storage vessel.
Important limits
Drainage, water quality, evaporation, plant choice, and local rules still need a human decision. Do not use a contaminated roof or storage vessel for edible crops without appropriate treatment and advice.