Humidity Ratio Calculator

Calculate humidity ratio and moisture content from temperature and relative humidity per ASHRAE standards.

Air Conditions

F
%

Atmospheric Conditions

in Hg
ft

Comfort Zone Reference

ConditionHumidity RatioGrains/lb
Minimum Comfort0.00428
ASHRAE Summer0.01284
Maximum Comfort0.016112
Saturation at 55F0.00963

Formulas Used

Humidity Ratio: W = 0.622 x Pw / (Patm - Pw)

Enthalpy: h = 0.240 x T + W x (1061 + 0.444 x T)

Specific Volume: v = 0.370486 x (T + 459.67) x (1 + 1.6078 x W) / Patm