Vapor Pressure Deficit Calculator







Formula

The formula to calculate the vapor pressure deficit is:

\[ VPD = SVP - AVP \]

Where:

Alternatively, using relative humidity:

\[ VPD = SVP \times \left(1 - \frac{RH}{100}\right) \]

Where:

What is Vapor Pressure Deficit?

A vapor pressure deficit, or VPD for short, is the difference between the saturated vapor pressure and the actual current vapor pressure. The saturated vapor pressure is the maximum amount of water vapor a body of air at a given temperature can hold.

Example Calculation

Example 1:

Step 1: Calculate the vapor pressure deficit:

\[ VPD = 30 - 20 = 10 \]

Example 2:

Step 1: Calculate the vapor pressure deficit using RH:

\[ VPD = 40 \times \left(1 - \frac{50}{100}\right) = 40 \times 0.5 = 20 \]