Garden watering time calculator
One millimetre of water over one square metre is exactly one litre.
m²
mm
L/min
%
Watering time
98.0minutes
- Watering time
- 1.63 hours
- Water needed on the soil
- 1000 L
- Water to supply
- 1176 L
Show the working
- Area to water = 50
- Target water depth = 20
- Hose or sprinkler flow = 12
- Water reaching the target area = 85
- Water needed on the soil = 50*20 = 1000
- Water to supply = 1000/(85/100) = 1176.47
- Watering time = 1176.47/12 = 98.0392
- Watering time = 98.0392/60 = 1.633 99
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
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The formula
- litres needed = area in m² x depth in mm
- time = supplied litres / flow
Wind, runoff, soil infiltration and overlapping sprinkler patterns affect delivery efficiency.