Psychrometric Calculator

Dew point, GPP, vapor pressure from temperature and RH.

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Formula and source

Saturation vapor pressure es(T) = 6.112 × exp((17.62 × T) / (243.12 + T)) mb (August-Roche-Magnus). RH × es = e (actual vapor pressure). Dew point Td = (243.12 × ln(e/6.112)) / (17.62 - ln(e/6.112)). GPP = 7000 × (0.622 × e) / (P - e).

August-Roche-Magnus formulation by name; ASHRAE Handbook (Fundamentals) Chapter 1 (Psychrometrics) by name.

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