Chemistry

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Vapor Pressure of Water Calculator.

Calculate water or ice saturation pressure with the declared Magnus correlation and visible temperature limits.

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Results update as you type.

Vapor pressure: 3.161736 kPa

Vapor pressure

3.161736kPa
Vapor pressure: 3,161.736036 Pa

Vapor pressure

3,161.736036Pa

How to Use

Every model convention and source-dependent parameter is visible. Results update automatically after each edit.

Use Cases

Meteorology and Weather Forecasting

Determine saturation vapor pressure to assess humidity, dew point, and potential for condensation or precipitation in atmospheric models.

Example: Input a temperature of 25°C to get the saturation vapor pressure for a weather report.

Engineering and HVAC Design

Calculate vapor pressure for designing drying processes, humidification systems, or predicting moisture behavior in industrial settings.

Example: Use a temperature of 80°C to estimate vapor pressure for a drying oven design.

Frequently Asked Questions

What is the Magnus correlation for vapor pressure?
The Magnus correlation is a widely used empirical formula that relates saturation vapor pressure to temperature. It provides accurate estimates for water (above 0°C) and ice (below 0°C) within specified temperature ranges, making it convenient for meteorological and engineering calculations.
What temperature limits does this calculator use?
The calculator uses the Magnus correlation with visible temperature limits. For water, the valid range is typically from -40°C to 50°C, and for ice, from -40°C to 0°C. These limits ensure the accuracy of the correlation.
Can I use this calculator for both water and ice?
Yes. The calculator automatically applies the appropriate Magnus coefficients based on the temperature you input. If the temperature is below 0°C, it calculates the saturation vapor pressure over ice; if above 0°C, it calculates over water.

Tips & Common Mistakes

Tips

  • Ensure your temperature is within the visible limits shown on the calculator to get accurate results.
  • For temperatures below 0°C, the calculator uses ice coefficients; for above 0°C, it uses water coefficients.
  • Double-check your temperature unit (Celsius) before entering it to avoid errors.
  • Use the result as a reference for saturation conditions; actual vapor pressure may vary with other factors.

Common Mistakes to Avoid

  • Entering a temperature outside the valid range, which can lead to inaccurate or invalid results.
  • Confusing the saturation vapor pressure with actual vapor pressure, which depends on relative humidity.
  • Assuming the calculator works for all temperatures without checking the visible limits.

Last updated: August 13, 2026