Part of the Agriculture collection — 4 tools available
Irrigation Calculator — Gallons Per Hour
Calculate water requirements for your field or garden. Estimate gallons per hour, daily volume, and total water based on area and application depth.
About This Calculator
Proper irrigation scheduling means delivering the right amount of water at the right time — not drowning your plants with saturated soil or letting them wilt from underwatering during critical growth stages. Sizing drip lines, selecting the right pump, and planning watering schedules all start with knowing your gallons-per-hour requirement. The conversion from square footage and application depth to flow rate trips up many gardeners and small farmers. Our irrigation calculator converts your irrigated area and desired weekly depth into gallons per hour so you can size your system correctly.
The Formula Behind This Calculator
Water (gal) = Area * Depth * 0.623 Runtime (min) = Water needed / Flow rate Morning watering reduces evaporation 30%.
Understanding the math helps you verify results and make better decisions for your project.
How to Use
- 1Enter the irrigated area in square feet.
- 2Set desired water depth in inches per week.
- 3Enter how many hours per day your system runs.
- 4Enter watering days per week.
- 5Click Calculate for GPH and total weekly volume.
When to Use
- →Sizing a drip irrigation system or pump for a garden, greenhouse, or small farm
- →Planning weekly watering schedules during drought conditions to avoid under- or over-watering
- →Comparing water costs between sprinkler and drip systems for the same area
Tips
- ✓Water early morning (5-9 AM) to minimize evaporation losses — you can lose 30-50% watering in midday heat
- ✓Use drip irrigation instead of sprinklers wherever possible — drip is 90-95% efficient vs 50-70% for overhead
- ✓Adjust your weekly depth based on rainfall — a cheap rain gauge saves water and prevents overwatering
FAQ
How much water does a garden need per week?
Most vegetables need 1-2 inches per week. Tomatoes and melons may need 2-3 inches during fruiting. Adjust for rainfall.
How do I convert acre-inches to gallons?
One acre-inch equals 27,154 gallons. For smaller areas, 1 cubic foot = 7.48 gallons.
Is drip irrigation more efficient than sprinklers?
Yes. Drip systems are 90-95% efficient vs 50-70% for sprinklers. Drip puts water at the root zone with minimal evaporation.
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