How to use the reference evapotranspiration from pan calculator
Estimate reference evaporation from an evaporation pan reading and a pan coefficient. Enter pan evaporation, pan coefficient in the fields above; the reference evaporation, monthly evaporation (30 days) are computed instantly and plotted on the chart so you can see how the answer changes.
Common searches this calculator answers include “pan evaporation coefficient”, “evaporation from pan reading”, “reference evaporation”, “calculate reference evapotranspiration from pan”, “find reference evaporation”.
Formula
Variables
- ep — Pan evaporation (mm/day)
- kp — Pan coefficient
Worked example
With pan evaporation = 8 mm/day, pan coefficient = 0.7, the calculator gives reference evaporation ≈ 5.6 mm/day; monthly evaporation (30 days) ≈ 168 mm/month.
Frequently asked questions
What is the reference evapotranspiration from pan calculator used for?
Estimate reference evaporation from an evaporation pan reading and a pan coefficient. It helps with questions such as “pan evaporation coefficient”, “evaporation from pan reading”, “reference evaporation”.
What is the formula for the reference evapotranspiration from pan calculation?
Reference evaporation (mm/day) = ep × kp. Monthly evaporation (30 days) (mm/month) = [Reference evaporation] × 30. Here ep is pan evaporation (mm/day), kp is pan coefficient.
What inputs do I need for the reference evapotranspiration from pan calculator?
You need pan evaporation in mm/day, pan coefficient. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use the reference evapotranspiration from pan calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the reference evapotranspiration from pan result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.