Ideal Gas at STP Calculator
Calculate gas volume using the ideal gas law (PV = nRT).
The ideal gas law PV = nRT relates pressure, volume, temperature and amount of gas. At standard temperature and pressure (0°C, 1 atm), one mole of any ideal gas occupies 22.414 liters. This calculator handles any conditions - useful for lab work, stoichiometry and engineering gas calculations.
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Frequently asked questions
Exactly 22.414 liters at standard temperature (273.15 K) and pressure (1 atm). This is the molar volume and applies to any ideal gas regardless of identity.
V = nRT/P. For 1 mol at 25°C (298.15 K) and 1 atm: V = 1 × 0.08206 × 298.15 / 1 = 24.47 liters.
R = 0.08206 L·atm/(mol·K) when using liters and atmospheres. In SI units, R = 8.314 J/(mol·K). The value depends on the units you use.
Volume is directly proportional to temperature (in Kelvin). Doubling the absolute temperature doubles the volume. Going from 300 K to 600 K doubles the volume at constant pressure.
At 25°C and 1 atm, air density = PM/(RT) = 1 × 28.97 / (0.08206 × 298.15) = 1.184 g/L. At 0°C it is 1.293 g/L.