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What does the Irrigation run-time & water depth calculate?
How long should irrigation run to apply a chosen water depth? This calculator uses watered area, target water depth, measured system flow, and watering sessions to estimate irrigation runtime immediately in your browser.
With the values currently entered, the result is 2.8 hours — total irrigation runtime. It also shows runtime per session, water volume, and sessions.
How to use the Irrigation run-time & water depth
- Replace the example values with your own numbers.
- Review the result and supporting figures as they update automatically.
- Check the formula and assumptions before using the estimate for a decision.
Inputs used
- Watered area — entered in m²
- Target water depth — entered in mm
- Measured system flow — entered in L/min
- Watering sessions — entered in sessions
Irrigation run-time & water depth formula
Litres required = area in m² × depth in mm; runtime = litres ÷ flow litres per minute
Assumptions
- One millimetre over one square metre equals one litre.
- Flow is even across the area and remains constant during watering.
Practical guide
Irrigation run-time & water depth example and edge cases
How long should irrigation run to apply a chosen water depth? Let's use a concrete example, then look at the assumptions that can move the answer.
Example: A practical irrigation run-time & water depth scenario
For this example, use watered area of 500 m², target water depth of 10 mm, measured system flow of 30 L/min, and watering sessions of 2 sessions. These are starting values, so replace them with numbers that match your situation.
- Watered area
- 500 m²
- Target water depth
- 10 mm
- Measured system flow
- 30 L/min
- Watering sessions
- 2 sessions
Calculated result2.8 hourstotal irrigation runtime
Start with total irrigation runtime. Then check runtime per session, water volume, and sessions to understand what sits behind the main result.
Example results use the default display profile. The calculator above follows your selected country and units.
How to read the result
- Read the main result first. The supporting figures for runtime per session, water volume, and sessions explain how the estimate is built.
- The method is Litres required = area in m² × depth in mm; runtime = litres ÷ flow litres per minute. Keep the units consistent and use values from the same time period.
Edge cases worth checking
When watered area is unusual
One millimetre over one square metre equals one litre. Double-check this input before relying on the result.
When watering sessions is uncertain
Flow is even across the area and remains constant during watering. Run a lower and higher value to see a useful range.
What changes the result most
Watered area
Measure watered area with the same unit shown beside the input. Convert first if your source uses another unit.
Target water depth
Measure target water depth with the same unit shown beside the input. Convert first if your source uses another unit.
Measured system flow
Measure measured system flow with the same unit shown beside the input. Convert first if your source uses another unit.
Try a different scenario
Small changes show whether the answer is stable or sensitive.
Watered area: 10% lower
450 m²2.5 hourstotal irrigation runtime
Watered area: 10% higher
550 m²3.1 hourstotal irrigation runtime
Target water depth: 10% higher
11 mm3.1 hourstotal irrigation runtime
Common mistakes
Check watered area
One millimetre over one square metre equals one litre. Make sure this matches the number you enter.
Keep watering sessions consistent
Flow is even across the area and remains constant during watering. Use the same units and time period throughout the calculation.
Do not rely on one irrigation run-time & water depth scenario
Run a cautious case and an optimistic case. The range is often more useful than one exact-looking number.
Use this result well
How long should irrigation run to apply a chosen water depth?
Weather, soil, product coverage, and site conditions can change the quantity or cost.