Air Density and Specific Weight Equations and Calculator

Engineering Calculators
Engineering Physics

Air Density and Specific Weight Equations and Calculator:

The density of air, ρ (Greek: rho) (air density), is the mass per unit volume of Earth's atmosphere. Air density, like air pressure, decreases with increasing altitude. It also changes with variation in temperature or humidity. At sea level and at 15 °C, air has a density of approximately 1.225 kg/m3 (0.001225 g/cm3, 0.0023769 slug/ft3, 0.0765 lbm/ft3) according to ISA (International Standard Atmosphere).

 Temperature F = Relative Humidity % RH = Barometer B (in) = Altitude (ft Above Sea Level) A = Equation Altitude (meters) = A*12*2.54/100 Temperature Degrees C = ((F-32)*5/9) Temperature kelvin k = C+273 Barometer  (mbar) = B/(29.92/1013) Barometer (mb) = 1013*EXP(-B7/7000) Barometer (in) = mb*(29.92/1013) Ms (g/kg) = 3.884266*10^((7.5*k)/(237.7+C)) M (g/kg) = Ms*RH/100 Tvc = ((1+1.609*M)/(1+M))*k Es (saturation pressure mb) = 6.11*10^(7.5*C/(237.7+k)) E (Vapor Ressure mb) = (RH*Es)/100 Tdc = (-430.22+237.7*LN(B17))/(-LN(B17)+19.08) Tdf = Tdc*9/5+32 Equation: D=P/(T*R) = Std Density (100) Temp, Altitude, Pressure, and Humidity Barometer (alt-station) as = mb*EXP(-B7/7000) D (air density) (kg/m3) ad = (as*100)/(B9*287) Corrected Density = D (virt air density) (kg/m3) vad = (as*100)/((B15+273)*287) Corrected Density =