Math and Science
VPD Calculator
VPD Calculator calculate air and leaf saturation vapor pressure, actual vapor pressure, and leaf vapor pressure deficit from temperature and humidity.
Math and Science
VPD Calculator
Calculate air and leaf saturation vapor pressure, actual vapor pressure, and leaf vapor pressure deficit from temperature and humidity.
Formula
SVP(T)=0.6108 exp(17.27T/(T+237.3)); VPD_leaf = SVP(leaf) - RH x SVP(air).
About the VPD Calculator
Calculate air and leaf saturation vapor pressure, actual vapor pressure, and leaf vapor pressure deficit from temperature and humidity. This tool keeps the requested measurements separate and applies the named method instead of substituting an unrelated general estimate.
How the VPD Calculator Works
The Tetens relationship estimates saturation pressure in kilopascals, while relative humidity supplies actual air vapor pressure.
Formula
SVP(T)=0.6108 exp(17.27T/(T+237.3)); VPD_leaf = SVP(leaf) - RH x SVP(air).
The calculation runs in your browser. Values are validated for required ranges, compatible units, and method-specific restrictions before results are displayed.
Required Inputs
- Air temperature (required) - enter in C.
- Relative humidity (required) - enter in %.
- Leaf temperature (required) - enter in C.
Results Reported
The result panel reports the final answer and the intermediate quantities needed to check the calculation:
- Air saturation vapor pressure (kPa)
- Leaf saturation vapor pressure (kPa)
- Actual vapor pressure (kPa)
- Air VPD (kPa)
- Leaf VPD (kPa)
VPD Calculator Example
Select Example Data in the calculator to load this reproducible input set:
| Input | Example value |
|---|---|
| Air temperature | 25 C |
| Relative humidity | 60 % |
| Leaf temperature | 24 C |
How to Use the Calculator
- Confirm that the calculator title and formula match the quantity you need.
- Enter every required value using the unit shown with its field.
- Select Example Data to inspect a valid input set, or enter your own values and select Calculate.
- Review all reported values and the displayed formula before using the answer.
- Use Copy Result or Download CSV when you need a reusable record.
Accuracy and Limitations
Sensor placement, canopy temperature, radiation, airflow, and condensation affect plant conditions. The approximation is intended for typical horticultural temperatures.
Keep units consistent, use measurements that represent the actual situation, retain full precision during the calculation, and round only the final answer. Professional decisions may require current official rules, field measurements, laboratory methods, or specialist review.
Frequently Asked Questions
What does the VPD Calculator calculate?
Calculate air and leaf saturation vapor pressure, actual vapor pressure, and leaf vapor pressure deficit from temperature and humidity.
Which formula does the VPD Calculator use?
SVP(T)=0.6108 exp(17.27T/(T+237.3)); VPD_leaf = SVP(leaf) - RH x SVP(air). The Tetens relationship estimates saturation pressure in kilopascals, while relative humidity supplies actual air vapor pressure.
How should I use the VPD Calculator result?
Sensor placement, canopy temperature, radiation, airflow, and condensation affect plant conditions. The approximation is intended for typical horticultural temperatures.