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 the volume occupied by a gas using V = nRT/P from the ideal gas law. Given the number of moles, temperature, and pressure, you get the volume in liters, milliliters, cubic meters, cubic feet, and gallons.
Understanding gas volume is essential for container sizing, chemical reactor design, and gas storage calculations. One of the most important results in chemistry is that one mole of any ideal gas at standard temperature and pressure (STP, 0°C and 1 atm) occupies exactly 22.414 liters — regardless of the type of gas.
This calculator provides multi-unit volume output, container size comparisons to help visualize the result, a reference table showing how volume scales with moles, and supporting calculations including gas mass, density, and molar volume. Check the example with realistic values before reporting. Use the steps shown to verify rounding and units. Cross-check this output using a known reference case. Use the example pattern when troubleshooting unexpected results.
Gas volume calculations are needed for gas cylinder sizing, chemical reaction planning, balloon inflation, HVAC duct sizing, and many more applications. This calculator handles all units and provides intuitive container-size comparisons. Keep these notes focused on your current workflow. Tie the context to real calculations your team runs. Use this clarification to avoid ambiguous interpretation. Align the note with how outputs are reviewed.
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.
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.