When to use this calculator
Convert collected water volume and opening area into rainfall depth. Collector geometry and splash, wind and evaporation can affect measurement.
Explore the irrigation & applied water calculators for other questions in this topic. For a related calculation, use the Rainfall Irrigation Offset Calculator: Subtract entered effective rainfall from a chosen irrigation-depth target.
PUTTING IT INTO PRACTICE
Rain Gauge Catch Depth: 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 |
|---|---|
| Collected water (mL) | 100 |
| Collector opening area (cm²) | 100 |
| Result | 10 mm |
- Check the input labels and enter the example values above.
- Apply the relationship: Rain depth in mm = collected mL/opening cm² × 10.
- The result is 10 mm, rounded for display.
How to interpret your result
Collector geometry and splash, wind and evaporation can affect measurement.
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 rain gauge catch depth calculator useful?
Convert collected water volume and opening area into rainfall depth. Collector geometry and splash, wind and evaporation can affect measurement.
How do I use the rain gauge catch depth calculator?
Enter collected water (ml), collector opening area (cm²). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Rain depth in mm = collected mL/opening cm² × 10.
What should I check before using the result?
Collector geometry and splash, wind and evaporation can affect measurement.
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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