National Weather Service United States Department of Commerce

Vapor Pressure

by Tim Brice and Todd Hall
 
 
Enter a temperature or a dewpoint or both:
Vapor Pressure
If you want the saturated vapor pressure enter the air temperature:  saturated vapor pressure:
  Fahrenheit Celsius Kelvin mb in of HG mm HG 
hPA kPA lbs per square in
If you want the actual vapor pressure enter the dewpoint:  actual vapor pressure:
  Fahrenheit Celsius Kelvin mb in of HG mm HG 
hPA kPA lbs per square in
If you enter both the air temperature and the dewpoint you'll get a bonus answer.  relative humidity - requires both temp and dewpoint
  %

 

What is the formula for the vapor pressure script?