VPD Calculator & Reference Chart
Calculate Vapor Pressure Deficit (VPD) from any temperature and humidity combination. See ideal ranges per growth stage and a color-coded reference chart.
Leaf VPD
1.26kPa
Air VPD
1.47
Tap any cell
Leaf temp 76.0°F
| °F\RH | 30 | 35 | 40 | 45 | 50 | 55 | 60 | 65 | 70 | 75 | 80 | 85 | 90 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 60° | 1.1 | 1.0 | 0.9 | 0.8 | 0.8 | 0.7 | 0.6 | 0.5 | 0.4 | 0.3 | 0.2 | 0.1 | 0.1 |
| 62° | 1.2 | 1.1 | 1.0 | 0.9 | 0.8 | 0.7 | 0.6 | 0.5 | 0.4 | 0.3 | 0.2 | 0.2 | 0.1 |
| 64° | 1.3 | 1.2 | 1.1 | 1.0 | 0.9 | 0.8 | 0.7 | 0.6 | 0.5 | 0.4 | 0.3 | 0.2 | 0.1 |
| 66° | 1.4 | 1.3 | 1.2 | 1.1 | 0.9 | 0.8 | 0.7 | 0.6 | 0.5 | 0.4 | 0.3 | 0.2 | 0.1 |
| 68° | 1.5 | 1.4 | 1.2 | 1.1 | 1.0 | 0.9 | 0.8 | 0.7 | 0.5 | 0.4 | 0.3 | 0.2 | 0.1 |
| 70° | 1.6 | 1.5 | 1.3 | 1.2 | 1.1 | 1.0 | 0.8 | 0.7 | 0.6 | 0.5 | 0.3 | 0.2 | 0.1 |
| 72° | 1.7 | 1.6 | 1.4 | 1.3 | 1.2 | 1.0 | 0.9 | 0.8 | 0.6 | 0.5 | 0.4 | 0.2 | 0.1 |
| 74° | 1.8 | 1.7 | 1.5 | 1.4 | 1.2 | 1.1 | 1.0 | 0.8 | 0.7 | 0.5 | 0.4 | 0.2 | 0.1 |
| 76° | 1.9 | 1.8 | 1.6 | 1.5 | 1.3 | 1.2 | 1.0 | 0.9 | 0.7 | 0.6 | 0.4 | 0.3 | 0.1 |
| 78° | 2.1 | 1.9 | 1.8 | 1.6 | 1.4 | 1.3 | 1.1 | 0.9 | 0.8 | 0.6 | 0.4 | 0.3 | 0.1 |
| 80° | 2.2 | 2.1 | 1.9 | 1.7 | 1.5 | 1.4 | 1.2 | 1.0 | 0.8 | 0.7 | 0.5 | 0.3 | 0.1 |
| 82° | 2.4 | 2.2 | 2.0 | 1.8 | 1.6 | 1.4 | 1.3 | 1.1 | 0.9 | 0.7 | 0.5 | 0.3 | 0.1 |
| 84° | 2.5 | 2.3 | 2.1 | 1.9 | 1.7 | 1.5 | 1.3 | 1.1 | 0.9 | 0.7 | 0.5 | 0.3 | 0.1 |
| 86° | 2.7 | 2.5 | 2.3 | 2.1 | 1.9 | 1.6 | 1.4 | 1.2 | 1.0 | 0.8 | 0.6 | 0.4 | 0.2 |
| 88° | 2.9 | 2.7 | 2.4 | 2.2 | 2.0 | 1.8 | 1.5 | 1.3 | 1.1 | 0.9 | 0.6 | 0.4 | 0.2 |
| 90° | 3.1 | 2.8 | 2.6 | 2.4 | 2.1 | 1.9 | 1.6 | 1.4 | 1.2 | 0.9 | 0.7 | 0.4 | 0.2 |
| 92° | 3.3 | 3.0 | 2.8 | 2.5 | 2.3 | 2.0 | 1.7 | 1.5 | 1.2 | 1.0 | 0.7 | 0.5 | 0.2 |
| 94° | 3.5 | 3.2 | 2.9 | 2.7 | 2.4 | 2.1 | 1.9 | 1.6 | 1.3 | 1.0 | 0.8 | 0.5 | 0.2 |
Peak transpiration for canopy growth
What is VPD?
Vapor Pressure Deficit (VPD) is the difference between the amount of moisture in the air and the maximum it can hold at a given temperature. It determines how quickly your plant transpires — which drives nutrient uptake, photosynthesis, and growth rate.
Leaf VPD is the more accurate number because it accounts for the leaf surface being slightly cooler than the surrounding air during active transpiration. Use Leaf VPD (the orange card above) to dial in your environment.
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