Ideal Gas Temperature Calculator — Solve PV = nRT for T
Solve the ideal gas law PV = nRT for temperature: enter pressure (kPa), volume (L), and the number of moles to get the gas temperature in Kelvin, Celsius, and Fahrenheit.
kPa
L
mol
Absolute temperature of the ideal gas (PV = nRT solved for T)
- 1
Numerator P × V
101.325 × 22.4 = 2,269.68P in kPa and V in L: the kPa × L = J cancellation means the result is in joules. - 2
Denominator n × R
1 × 8.314 = 8.314 - 3
Temperature T = PV / (nR)
2,269.68 ÷ 8.314 = 272.99
How does this calculator work?
T = PV/(nR) where R = 8.314 J/(mol·K). Enter pressure in kPa, volume in L, and moles to get temperature in Kelvin (then Celsius and Fahrenheit). The default STP inputs (101.325 kPa, 22.4 L, 1 mol) return 273 K (0 °C). The ideal gas model is accurate at low-to-moderate pressures well above the condensation point.
Formula
How this is calculated
The ideal gas law PV = nRT ties together the four macroscopic state variables of a gas: absolute pressure P (Pa), volume V (m³), amount of substance n (mol), and absolute temperature T (K). The universal gas constant R = 8.314 J mol⁻¹ K⁻¹ is the proportionality factor. Rearranging for temperature gives T = PV/(nR).
This calculator accepts pressure in kilopascals and volume in litres — laboratory-friendly units. Because 1 kPa × 1 L = 1 Pa × 1000 × 1 m³/1000 = 1 Pa m³ = 1 J, the prefixes cancel and the formula T = P_kPa × V_L / (n × 8.314) gives the correct answer in Kelvin directly. The default inputs (P = 101.325 kPa, V = 22.4 L, n = 1 mol) reproduce the STP condition of ≈ 273 K (0 °C), confirming the calculation.
The ideal gas model treats molecules as point masses with no intermolecular forces — an excellent approximation at low pressures and temperatures well above the boiling point of the gas. Near liquefaction or at high pressures (several MPa), use a real-gas equation of state (van der Waals, Peng-Robinson) for accurate results.
Frequently asked questions
The ideal gas law is derived from the kinetic theory of gases, in which pressure is proportional to the average kinetic energy of molecules. That energy is proportional to absolute temperature (Kelvin), which is zero at absolute zero. Using Celsius or Fahrenheit — which have arbitrary zero points — would give physically wrong results.
The defaults (101.325 kPa, 22.4 L, 1 mol) are Standard Temperature and Pressure (STP), defined as 0 °C (273.15 K) and 1 atm. The molar volume of an ideal gas at STP is 22.414 L/mol, so the calculator returns ≈ 273 K — confirming the formula.
Yes, with modest error. At conditions near room temperature and atmospheric pressure, real gases behave very close to ideal: errors are typically below 1%. At high pressures or low temperatures (near condensation), significant deviations occur and a more detailed equation of state should be used.
Also known as
TG we-Calculate Editorial Team. (2026). Ideal Gas Temperature Calculator — Solve PV = nRT for T [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/ideal-gas-temperature-calculator
TG we-Calculate Editorial Team. "Ideal Gas Temperature Calculator — Solve PV = nRT for T." TG we-Calculate. 2026. https://we-calculate.com/calculator/ideal-gas-temperature-calculator.
TG we-Calculate Editorial Team, "Ideal Gas Temperature Calculator — Solve PV = nRT for T," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/ideal-gas-temperature-calculator
@misc{wecalculate_ideal_gas_temperature_calculator, title = {Ideal Gas Temperature Calculator — Solve PV = nRT for T}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/ideal-gas-temperature-calculator}}, year = {2026}, note = {TG we-Calculate} }
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