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Rainfall Calculator

Find the water volume from rainfall over an area.

Rainfall depth

Area

Calculated Output

Water volume 623.38

Water volume 2,359.74

Formula: gallons = depth (ft) × area × 7.48052

Step-by-Step Breakdown

1. Values used:

2. Rainfall depth = 1

3. Area = 1,000

5. Water volume = 623.38

6. Water volume = 2,359.74

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The math behind it

volume (ft³) = depth (ft) × area; × 7.48052 for US gallons. Great for rainwater harvesting.

1 in over 1,000 ft² → ~623 gallons.

Roof catchment?

Use the roof's footprint area for harvesting estimates.