Leaf Vapor Pressure Deficit Calculator
Compare air and leaf-to-air vapor-pressure deficits using independently entered leaf temperature.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Use the FAO saturation-pressure relation at each temperature and subtract the same ambient actual vapor pressure.
Actual vapor pressure=es(Tair) RH/100; leaf VPD=es(Tleaf)−actual vapor pressure
Worked example
At equal leaf and air temperatures, leaf-to-air and air VPD are equal. A cooler leaf gives a smaller leaf-to-air deficit.
Assumptions and input details
Ideal saturated leaf interior, temperature range 0–50°C, no plant species target or growing recommendation. Negative leaf deficit indicates ambient vapor pressure exceeds saturation at the entered leaf temperature; no transpiration rate or condensation amount is inferred.
References: FAO: saturation and actual vapor pressure
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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