VPD Calculator & Chart

Vapor Pressure Deficit for Plants & Greenhouses

Calculate the Vapor Pressure Deficit (VPD) for your growing environment. Enter temperature and humidity to get instant VPD results and generate a VPD chart for any range.

Examples

See how to use the VPD Calculator & Chart with real-world scenarios.

Single VPD Calculation

Single VPD Calculation

Calculate VPD for 25°C and 60% humidity.

Temperature: 25

Relative Humidity: 60 %

Temperature Unit: Celsius (°C)

Mode: Single Value

VPD for 77°F and 50% Humidity

VPD for 77°F and 50% Humidity

Calculate VPD for 77°F and 50% humidity.

Temperature: 77

Relative Humidity: 50 %

Temperature Unit: Fahrenheit (°F)

Mode: Single Value

VPD Table for 20-30°C, 40-80% RH

VPD Table for 20-30°C, 40-80% RH

Generate a VPD table for temperatures 20-30°C and humidity 40-80%.

Step Size: 2

Temperature Unit: Celsius (°C)

Mode: VPD Table

Temperature Range: 20 - 30

Humidity Range: 40 - 80 %

VPD Chart for 65-85°F, 50-90% RH

VPD Chart for 65-85°F, 50-90% RH

Generate a VPD chart for temperatures 65-85°F and humidity 50-90%.

Step Size: 5

Temperature Unit: Fahrenheit (°F)

Mode: VPD Chart

Temperature Range: 65 - 85

Humidity Range: 50 - 90 %

Other Titles
Understanding the VPD Calculator & Chart: A Comprehensive Guide
Everything you need to know about Vapor Pressure Deficit (VPD) and its importance for plant growth.

What is VPD (Vapor Pressure Deficit)?

  • Definition and Importance
  • How VPD Affects Plants
  • VPD in Greenhouse Management
Vapor Pressure Deficit (VPD) is the difference between the amount of moisture in the air and how much moisture the air can hold when it is saturated. It is a key factor in plant transpiration and water uptake.
Why VPD Matters

VPD in Practice

  • Plants in low VPD environments may suffer from disease.
  • High VPD can cause excessive water loss and stress.

Step-by-Step Guide to Using the VPD Calculator & Chart

  • Inputting Temperature and Humidity
  • Choosing Calculation Mode
  • Interpreting Results
Enter the temperature and relative humidity of your environment. Select the calculation mode: single value, table, or chart. The calculator will provide VPD, SVP, and AVP values, and generate a chart or table if selected.
How to Use the Tool

Example Uses

  • Calculating VPD for a single greenhouse reading.
  • Generating a VPD chart for a week of climate data.

Real-World Applications of VPD Calculation

  • Greenhouse and Indoor Growing
  • Field Agriculture
  • Research and Education
VPD calculation is used by greenhouse managers, indoor growers, and researchers to optimize plant health and yield. It helps in setting climate control systems and understanding plant stress responses.
Practical Applications

Application Scenarios

  • Setting up climate control in a tomato greenhouse.
  • Teaching plant physiology in a classroom.

Common Misconceptions and Correct Methods

  • Confusing VPD with Humidity
  • Ignoring Temperature Effects
  • Incorrect Unit Conversions
Many growers focus only on humidity, but VPD is a more accurate indicator of plant water stress. Always use the correct temperature and humidity units, and understand how both affect VPD.
Avoiding Mistakes

Common Mistakes

  • Using °F instead of °C without conversion.
  • Assuming high humidity always means low VPD.

Mathematical Derivation and Examples

  • SVP and AVP Formulas
  • VPD Calculation Steps
  • Chart/Table Generation
SVP is calculated using temperature, AVP uses SVP and humidity, and VPD is the difference. For charts, the calculator computes VPD for each temperature and humidity pair in the selected range.
Calculation Formulas

Mathematical Examples

  • SVP = 0.6108 × exp[(17.27 × T) / (T + 237.3)]
  • VPD = SVP - AVP