When to use this calculator
Find watering duration from a water-volume target and flow rate. Use measured delivered flow and account separately for distribution losses or uneven coverage.
Explore the irrigation & applied water calculators for other questions in this topic. For a related calculation, use the Irrigation Volume Calculator: Translate a selected irrigation depth into water volume.
PUTTING IT INTO PRACTICE
Irrigation Runtime: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| Required applied water (L) | 1,000 |
| Measured system flow (L/min) | 20 |
| Result | 50 min |
- Check the input labels and enter the example values above.
- Apply the relationship: Runtime = required volume/system flow.
- The result is 50 min, rounded for display.
How to interpret your result
Use measured delivered flow and account separately for distribution losses or uneven coverage.
A water-budget conversion does not establish the crop’s requirement. Use measured flow and effective rainfall where possible. Distribution losses and runoff can make gross application differ from water retained in the root zone.
Frequently asked questions
Does one millimetre of rain equal one litre?
It equals one litre over each square metre of collection area. Total volume therefore depends on both depth and area.
When is the irrigation runtime calculator useful?
Find watering duration from a water-volume target and flow rate. Use measured delivered flow and account separately for distribution losses or uneven coverage.
How do I use the irrigation runtime calculator?
Enter required applied water (l), measured system flow (l/min). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Runtime = required volume/system flow.
What should I check before using the result?
Use measured delivered flow and account separately for distribution losses or uneven coverage.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
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