Ideal Gas Volume Calculator — Solve PV = nRT for V
Solve the ideal gas law for volume: enter pressure (kPa), temperature (°C), and amount of substance (mol) to get the gas volume in litres and cubic metres.
kPa
°C
mol
Volume of the ideal gas (PV = nRT solved for V)
- 1
Temperature (°C → K)
T = 0 + 273.15 = 273.15The ideal gas law requires absolute temperature in kelvin. - 2
Numerator n × R × T
1 × 8.314 × 273.15 = 2,270.9691 - 3
Volume V = nRT / P
2,270.9691 ÷ 101.325 = 22.4127
How does this calculator work?
V = nRT/P where R = 8.314 J/(mol·K). Enter pressure (kPa), temperature (°C, converted to Kelvin internally), and moles to get volume in litres. One mole at STP (0 °C, 101.325 kPa) occupies 22.414 L. Volume scales linearly with moles and temperature, and inversely with pressure.
Formula
How this is calculated
The ideal gas law PV = nRT relates pressure P (Pa), volume V (m³), amount of substance n (mol), and absolute temperature T (K) through the universal gas constant R = 8.314 J mol⁻¹ K⁻¹. Rearranging for volume gives V = nRT/P.
This calculator accepts Celsius for temperature, converting internally to Kelvin (T_K = T_C + 273.15) because absolute temperature must be used. Pressure is entered in kPa and volume is returned in litres. The unit algebra works cleanly: n (mol) × R (J mol⁻¹ K⁻¹) × T (K) ÷ P (kPa) = J/kPa = Pa m³/kPa = m³ × 1 000 = L. The default inputs (0 °C, 101.325 kPa, 1 mol) return the STP molar volume of 22.414 L/mol.
The ideal gas approximation is accurate for common gases (air, nitrogen, CO₂, noble gases) at pressures below a few MPa and temperatures well above each gas's boiling point. High pressures and low temperatures introduce intermolecular attraction and finite molecular volume — effects captured by the van der Waals or Peng-Robinson equations of state.
Frequently asked questions
Molar volume is the volume that one mole of gas occupies at a given temperature and pressure. At STP (0 °C, 101.325 kPa) it is 22.414 L/mol; at SATP (25 °C, 100 kPa) it is 24.789 L/mol. It increases with temperature (gas expands) and decreases with pressure (gas compresses).
Hotter molecules move faster and collide more forcefully with the container walls. To maintain the same pressure, the container must expand — this is Charles's law, a special case of PV = nRT where P and n are fixed. The volume is directly proportional to absolute temperature.
Yes. For an ideal gas mixture, use the total number of moles at total pressure, or each component's partial pressure and mole count separately — by Dalton's law the components act independently and sum to the total. The ideal gas law applies to each species and to the mixture.
Also known as
TG we-Calculate Editorial Team. (2026). Ideal Gas Volume Calculator — Solve PV = nRT for V [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/ideal-gas-volume-calculator
TG we-Calculate Editorial Team. "Ideal Gas Volume Calculator — Solve PV = nRT for V." TG we-Calculate. 2026. https://we-calculate.com/calculator/ideal-gas-volume-calculator.
TG we-Calculate Editorial Team, "Ideal Gas Volume Calculator — Solve PV = nRT for V," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/ideal-gas-volume-calculator
@misc{wecalculate_ideal_gas_volume_calculator, title = {Ideal Gas Volume Calculator — Solve PV = nRT for V}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/ideal-gas-volume-calculator}}, year = {2026}, note = {TG we-Calculate} }
Did this calculator help you?