Irrigation Water Calculator
Calculate irrigation water volume and watering time from area, application depth, and flow rate.
How it works
- 1Enter the area to irrigate, the desired application depth, and your system flow rate.
- 2The calculator multiplies area × depth for total volume (1 mm over 1 m² = 1 litre).
- 3Watering time is the volume divided by the flow rate.
Use cases
- Sizing irrigation runs for lawns, gardens, and sports fields.
- Estimating water cost and consumption for agriculture or landscaping.
- Scheduling drip or sprinkler systems to hit a target application depth.
Frequently asked questions
How is the water volume calculated?
Volume = area × application depth. 500 m² at 25 mm needs 500 × 0.025 = 12.5 m³ = 12,500 litres, because 1 mm over 1 m² equals 1 litre.
How is watering time calculated?
Watering time = volume ÷ flow rate. For 12,500 L at 2 L/s: about 6250 s ≈ 104 minutes. Raise the flow or split into zones to shorten it.
Should I adjust for efficiency and evapotranspiration?
Yes. Divide by the system’s distribution uniformity (≈ 0.7–0.9) for the gross volume, and use local evapotranspiration rates to set how often to irrigate.
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