Gas Density (kg/m³) NTP STP Acetylene (C2H2) 1,092 1,17 Air 1,205 1.293 Ammonia (NH3) 0,717 0,769 Argon (Ar) 1,661 1,78 Butane (C4H10) 2,489 2,5 Carbon dioxide (C02) 1,842 1,977 Carbon monoxide (C0) 1,165 1,25 Chlorine (Cl2) 2,994 3,21 Ethane (C2H6) 1,264 - Ethyne (C2H4) - 1,26 Fluorine (F2) 1,574 1,7 Helium (He) 0,1664 0,178 Hydrogen (H2) 0,0893 0,09		Gas Density (kg/m³) NTP STP Hydrogen Chloride (HCl) 1,528 - Hydrogen Sulfide (H2S) 1,434 - Krypton (Kr) - 3,73 Methane (CH4) 0,668 0,717 Neon (Ne) - 0,90 Nitric Oxide (NO) 1,249 - Nitrogen (N2) 1,165 1,25 Oxygen (O2) 1,331 1,429 Propane (C3H8) 1,882 - Propene (C3H6) 1,748 - Radon (Rn) - 9,73 Sulfur Dioxide (SO2) 2,279 2,926 Xenon (Xe) - 5,89
NTP - Gas density at Normal conditions, Temperature (25ºC) and Pressure (101.325 kPa) STP - Gas density at Standard conditions, Temperature (0ºC) and Pressure (101.325 kPa)

Gas density calculation

	Density relation up to ideal gas equations. d: Density P: Pressure T: Temperature

d1	=	d2	· (	P1	·	T2	) / (	P2	·	T1	)
g/cm³ g/mm³ kg/m³ lb/ft³		g/cm³ g/mm³ kg/m³ lb/ft³		atm bar inH2O inHg kp/cm² kPa in/ft2 lbf/ft2 MPa mbar mH2O mmH2O mmHg mmWC mWC Pa PSI torr		ºC ºF ºK ºR		atm bar inH2O inHg kp/cm² kPa in/ft2 lbf/ft2 MPa mbar mH2O mmH2O mmHg mmWC mWC Pa PSI torr		ºC ºF ºK ºR