Garden Watering Calculator — Gallons for a Given Watering Depth
Enter your garden area and the depth of water you want to apply (in inches). The calculator tells you how many gallons that corresponds to — useful for matching irrigation or hand-watering to a target depth.
What this calculator determines
It calculates how many gallons of water are needed to deliver a chosen depth of water over a given garden area.
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Examples
200 sq ft, 1 inch of water
200 sq ft × 1 in
Calculation
- Gallons: 200 × 1 × 0.623 = 124.7 gal
124.7 gallons
Assumptions & Conventions
- Conversion factor
- 1 inch of water over 1 square foot = 0.623 gallons; gallons = area × depth × 0.623.
- Target depth
- The depth is the water depth you want to apply, not soil depth.
- Watering need
- How much water your garden needs varies by crop, soil, and weather — enter the depth you have decided to apply.