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Irrigation & Water
Use Calculator Crop Water Need Calculator
Calculate crop evapotranspiration and field water volume from reference evapotranspiration and crop coefficient.
Irrigation & Water Calculators
Irrigation Water Requirement Calculator
Estimate net and gross irrigation depth and total water volume after rainfall and system-efficiency adjustments.
Free agriculture calculator
No signup requiredIrrigation Water Requirement Calculator
Your results
How to use the Irrigation Water Requirement Calculator
- Enter the requested field, crop, animal, equipment, or cost information.
- Keep every value in the unit shown beside its field.
- Select Calculate and review each result and assumption.
- Verify important decisions with local records, labels, extension guidance, or a qualified adviser.
Formula and method
Gross irrigation depth = max(ETc − effective rainfall, 0) × days ÷ efficiency fraction. Volume (m³) = depth (mm) × area (ha) × 10.
One millimetre over one hectare equals ten cubic metres. Dividing by efficiency accounts for delivery losses.
Worked example
Five hectares needing 5 mm/day with 1 mm/day effective rain for seven days at 80% efficiency requires 175 mm-field-ha, or 1,750 m³.
Understanding the result
Treat the calculated values as a planning estimate. Compare them with your field records, product information, local conditions and operational capacity before acting.
Important: Results depend on the accuracy of your inputs and the assumptions shown. Local soil, weather, crop, animal and market conditions can change the appropriate decision.
Frequently asked questions
What does the Irrigation Water Requirement Calculator calculate?
Estimate net and gross irrigation depth and total water volume after rainfall and system-efficiency adjustments.
How accurate is this calculator?
The arithmetic follows the formula shown, but the practical accuracy depends on your measurements, assumptions and local conditions.
Can I use the result for a final farm decision?
Use it for planning and comparison. Verify high-impact crop, chemical, engineering, financial or animal decisions with current local guidance and qualified advice.
Does BlogAgri store my calculator inputs?
No. The calculator runs in your browser and does not submit the entered values to BlogAgri.
