Reference ET per day
Weather and crop inputs · mm/day
Allowed range: 0 to 100
Crop Water Budget Calculator
Convert entered ETo, crop factor, effective rain and irrigation efficiency to litres.
Open this toolCrop water demand starts with entered weather and crop factors, then rain offsets part of the requirement.
Supply ETo, crop factor and effective rainfall on matching units. Apply efficiency to compare irrigation litres.
Inputs and controls
Entered crop coefficient
Weather and crop inputs · Kc
Allowed range: 0.01 to 3
Days in period
Weather and crop inputs · days
Allowed range: 1 to 365
Effective rain across period
Weather and crop inputs · mm
Allowed range: 0 to 10000
Garden area
Irrigated area · m²
Allowed range: 0.01 to 1000000
Application efficiency
Irrigated area · %
Allowed range: 0.01 to 100
How to use
- Enter reference ET per day, entered crop coefficient, days in period and effective rain across period.
- Enter garden area and application efficiency.
- Select Calculate result. Read the returned values alongside the assumptions below before copying, exporting or acting on the result.
Why use this tool
The staged calculation separates crop demand from the larger water amount needed after application losses.
Before relying on the result
ETc equals ETo × Kc. ETo and Kc are entered values, not weather forecasts; effective rain is already net of losses.
Tool limitations
ETc equals ETo × Kc. ETo and Kc are entered values, not weather forecasts; effective rain is already net of losses.
Questions
Is rainfall fetched automatically?
No. Enter suitable values for the period and site. Effective rain should already account for its relevant losses.
What should I check before using Crop Water Budget Calculator?
Check Reference ET per day, Entered crop coefficient, Days in period and Effective rain across period. Use the exact units shown beside the controls and replace any example values with your own inputs.
Source page last modified: 2026-10-04T13:08:12+00:00. This profile describes the tool; use its page to run it.
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