Calculate gas volume using V = nRT/P. Find volume from moles, temperature, and pressure with multi-unit results and container size comparisons.
The **Ideal Gas Volume Calculator** computes gas volume from V = nRT/P. Given moles, temperature, and pressure, it returns the result in liters, milliliters, cubic meters, cubic feet, and gallons so you can compare laboratory and practical container sizes at the same time.
One of the key ideal-gas results is molar volume: at STP, one mole of an ideal gas occupies 22.414 liters. That benchmark makes the calculator useful for chemistry problems, reactor sizing, and gas-storage estimates where you want to know how large a gas sample should be under a given set of conditions.
The page also includes container comparisons and supporting gas-property values such as mass, density, and molar volume, which helps you see whether the answer is physically plausible.
Volume is the form of the ideal-gas equation that most directly answers container-sizing questions. If you know the moles and state conditions, it is easier to check the resulting volume once than to reason about expansion or compression in your head.
V = nRT / P Where: V = volume (m³), n = moles, R = 8.31446 J/(mol·K), T = temperature (K), P = pressure (Pa) At STP: V = 22.414 L/mol
Result: 22.414 L
V = (1)(8.31446)(273.15) / (101325) = 0.022414 m³ = 22.414 L. This is the well-known molar volume at STP, confirming that one mole of any ideal gas occupies 22.414 liters at 0°C and 1 atm.
Amadeo Avogadro proposed in 1811 that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules. This revolutionary idea means the molar volume — volume per mole — is universal for ideal gases, regardless of chemical identity.
At STP (0°C, 101.325 kPa), the molar volume is 22.414 L/mol. At SATP (25°C, 100 kPa), it is 24.790 L/mol. These values serve as conversion factors in countless chemistry problems: if a reaction produces 2 moles of CO₂ at STP, the volume is simply 2 × 22.414 = 44.83 L.
**Gas Storage:** Natural gas pipelines operate at 40-100 atm, compressing the gas to a small fraction of its atmospheric volume. LNG (liquefied natural gas) achieves 600× volume reduction by cooling to -162°C, far more compact than compression alone.
**Chemical Reactors:** Reactor volume determines production capacity. Knowing the volume of gaseous reactants and products at reaction conditions is essential for sizing equipment, designing safety vents, and predicting flow rates.
Gases expand dramatically when heated or when pressure is released. A gas at 200 atm expands to 200× its compressed volume if suddenly released. Cryogenic liquids are even more dramatic — liquid nitrogen expands about 700× when it evaporates at room temperature, creating an asphyxiation hazard in enclosed spaces.
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The ideal gas law V = nRT/P does not contain any property specific to a particular gas. The volume depends only on n, T, and P, not on the type of molecules. This is Avogadro's hypothesis.
Only at STP (0°C, 1 atm). At room temperature (25°C, 1 atm), the molar volume is 24.465 L. IUPAC's new STP definition (0°C, 1 bar) gives 22.711 L/mol.
At constant pressure, volume is directly proportional to absolute temperature (Charles's Law). Doubling T (in Kelvin) doubles V.
At constant temperature, volume is inversely proportional to pressure (Boyle's Law). Doubling pressure halves the volume.
A standard compressed gas cylinder (50 L at 200 atm) holds about 10,000 L of gas at atmospheric pressure. The gas is compressed to 1/200th of its normal volume.
Yes — for volume calculations, use the total moles of all gases combined. Each gas contributes its mole fraction of the total, but the overall V = n_total × RT/P.