VPD calculator
Enter the air temperature and humidity at canopy height to see the vapor pressure deficit your plants feel, and whether it fits their growth stage.
1.05
kPa
- Leaf temperature
- Air VPD (no offset)
- Dew point
- Saturation pressure
Where you land
Temperature across, humidity down. Shaded bands are the target for the selected stage. Tap any cell for its value.
Too humid
Propagation
Vegetative
Flowering
Too dry
How this is calculated
Saturation vapor pressure uses the Magnus equation: SVP = 0.61078 × e^(17.27 × T ÷ (T + 237.3)) kPa, with T in °C. Actual vapor pressure of the air = SVP(air) × RH ÷ 100. Leaf VPD = SVP(leaf temperature) − actual vapor pressure. Target bands: propagation 0.4 to 0.8, vegetative 0.8 to 1.2, flowering 1.2 to 1.6 kPa.